This page carries the official NCERT chapter PDF of The Book That Saved the Earth Class 10 — the ninth and final chapter of the Class 10 English supplementary reader Footprints without Feet. It is a one-act comedy play in which Martian invaders mistake a book of nursery rhymes for a coded military report and call off their invasion of Earth.
The chapter runs 15 pages in the official NCERT PDF. The download is right below, followed by a scene-by-scene walkthrough, the characters, the key ideas and the textbook’s own questions with model answers.
Download the official NCERT chapter PDF
The official file from ncert.nic.in contains the full play text — title, cast list, stage directions and every line of dialogue — followed by the book’s glossary and its question sets (Read and Find Out, Think About It, Talk About It).
Download the official The Book That Saved the Earth Class 10 chapter PDF from ncert.nic.in to read the play exactly as printed in the NCERT supplementary reader, with the glossary and the question sets in the same file.
This chapter at a glance
The table below shows what the chapter contains — the play itself, the cast list, the glossary and the book’s own question sets. One thing to know before you open it: this is the final chapter of Footprints without Feet, so it closes both the book and the year’s supplementary reading.
What the play is about: a scene by scene walkthrough
This walkthrough follows the play in order so you can revise the whole plot in a few minutes. The play is built as a play within a play: almost everything you watch is a scene from 2040 that the Historian projects for her audience in the twenty-fifth century.
Scene 1: the Museum of Ancient History
The frame is set in the twenty-fifth century. A Historian sits in the Museum of Ancient History, Department of the Twentieth Century, beside a movie projector, and tells the audience that the twentieth century was called the Era of the Book.
She promises to show the famous Martian invasion of 2040, then switches on the historiscope — a projector that displays scenes from the past. The spotlight leaves her table and moves to Mars.
Scene 2: Mars Space Control
We meet the Great and Mighty Think-Tank, Commander-in-Chief of Mars, with his egg-shaped head and a robe decorated with stars and circles. He makes Apprentice Noodle repeat the full salutation — “O Great and Mighty Think-Tank, Ruler of Mars and her two moons” — consults his hand mirror (“Mirror, mirror, in my hand”) and plans to invade Earth before lunch.
Scene 3: the Centerville Public Library
Probe One has landed inside an ordinary small-town library, and the crew cannot identify what they see. Lieutenant Iota counts two thousand of these “peculiar items” and guesses at a storage barn; Sergeant Oop — who has visited seven galaxies — opens a book, puts it on his head and suggests a haberdashery.
Think-Tank, watching through enormous goggles, declares the building a crude refreshment stand and the item in Captain Omega’s hand a sandwich. He orders the crew to eat it; the order passes down the chain until Oop bites a corner of the book and finds it “dry as Martian dust”.
Scene 4: Noodle’s planted corrections
Noodle never contradicts his commander. He plants small doubts: “an insignificant bit of data floated into my mind” — the Earthlings do not eat these sandwiches, they use them as a communication device. Think-Tank adopts the idea at once: “That was my next point.” The objects become communication sandwiches, and the crew is ordered to listen to them.
Nothing is heard, so Noodle tries again: “a cloudy piece of information is twirling around in my head.” The Earthlings open the sandwiches and watch them. Think-Tank clarifies the point himself — the items are for eye communication — and when the crew reports “little lines and squiggles and dots”, he announces a code to be deciphered.
Scene 5: the vitamins and the three rhymes
At Noodle’s prompting, the crew is ordered to take the intelligence vitamins — “Remove vitamins… Present vitamins… Swallow vitamins” — and then read the colourful volume, which the audience can see is Mother Goose. Each nursery rhyme is read as a coded report, and Think-Tank’s alarm grows with every one; the key ideas table below shows the full chain of misreadings.
Scene 6: Humpty Dumpty and the panic
The third rhyme breaks him. Oop turns the large picture of Humpty Dumpty toward Think-Tank and the audience, and Think-Tank sees himself: “It’s me!” The line “had a great fall” reads as a plan to capture Mars Central Control, so he cancels the invasion and orders the whole planet evacuated to Alpha Centauri.
Scene 7: the Historian’s close
The spotlight returns to the Historian. In time, Earth resumes contact with Mars and the two become friendly; the wise Noodle replaces Think-Tank as ruler. Earthlings teach the Martians to read and open a model library in their capital, Marsopolis — but the one book they still will not touch is Mother Goose.
Characters in the play: who each one is and what they do
In a play, the cast list does the work a narrator does in a story: it tells you who is on stage and what each character is for, before a line of dialogue is spoken. This play has seven characters.
| Character | Who they are | What they do in the play |
|---|---|---|
| Historian | Museum guide in the twenty-fifth century | Opens and closes the play; introduces the Era of the Book, works the historiscope and narrates the 2040 invasion |
| Great and Mighty Think-Tank | Commander-in-Chief of the Martian forces; egg-shaped head, robe of stars and circles | Orders the invasion, misnames books as sandwiches, panics at Humpty Dumpty and evacuates Mars for Alpha Centauri |
| Apprentice Noodle | Think-Tank’s young assistant | Corrects his commander through planted hints and ends up ruling Mars |
| Captain Omega | Leader of Probe One | Reports to Mars, passes orders down the chain and reads the first rhyme, Mistress Mary |
| Lieutenant Iota | Probe officer | Counts two thousand books, passes the sandwich down to Oop and reads the second rhyme, Hey diddle diddle |
| Sergeant Oop | Literal-minded soldier | Has visited seven galaxies, wears a book as a hat, eats the sandwich and reads the third rhyme, Humpty Dumpty |
| Offstage voice | The mirror’s unseen answerer | Answers “You, sir,” and keeps Think-Tank’s vanity permanently fed |
The most-asked character question is how Noodle corrects a commander who has declared himself never wrong. His method is to refuse every argument. He offers each correction as a small, unimportant thing that drifted into his own head — “an insignificant bit of data floated into my mind” and “a cloudy piece of information is twirling around in my head”.
Think-Tank then adopts the idea as his own next point — “That was my next point”, “I will clarify it for you” — so the truth reaches the crew while the commander keeps his dignity. Noodle is never caught correcting him, and Think-Tank is never wrong.
Key ideas: the three rhymes, the sandwich joke and the play’s irony
The whole comedy runs on one mechanism: the Martians read innocent nursery rhymes as coded military intelligence, while the audience knows what the rhymes really are. That gap between what we know and what they believe is dramatic irony — and this table is the play’s engine in one view.
| Nursery rhyme | What Think-Tank reads into it | What it really is |
|---|---|---|
| Mistress Mary — silver bells, cockle shells, pretty maids all in a row | Earthlings combine agriculture and mining: they can grow crops of silver and grow high explosives as easily as flowers | A nonsense rhyme about a girl and her garden |
| Hey diddle diddle — the cow jumped over the moon, the dish ran away with the spoon | Earthlings have taught their cattle space techniques and may launch an attack of millions of cows; even their dogs have a sense of humour | Nonsense verse |
| Humpty Dumpty — sat on a wall, had a great fall; picture looks like Think-Tank | The Earthlings have seen him and are after his “balloon brain”; “had a great fall” means they plan to capture Mars Central Control — it is an invasion of Mars | A riddle about an egg that cannot be put together again |
The sandwich joke works by the same chain of corrections: refreshment stand, then sandwich, then communication sandwich, then listen to them, then eye communication, then a code to decipher. Each step is Think-Tank’s own new discovery, nudged forward by Noodle’s hints.
Because Think-Tank may never be wrong, every fresh guess must be fitted onto the last one instead of being questioned, so the error compounds instead of correcting itself.
The deeper irony is that the book wins by being misread, not by being understood. What actually saves Earth is a coincidence: the Humpty Dumpty picture happens to look like Think-Tank, and his vanity does the rest.
The comedy is never that the Martians are stupid — Oop has toured seven galaxies — but that they bring zero cultural knowledge to a planet that runs on books.
The theme: books versus electronic media
The play leaves its biggest question open (Think About It, Q3): are books being replaced by electronic media, and can we do away with them altogether? The play’s own answer is affectionate rather than argued.
The thing that saves Earth is a dusty old book of nursery rhymes — not an encyclopedia or a rocket manual — and the Martians only become safe, and friendly, once they learn to read. The ending quietly rewards Noodle’s humility over Think-Tank’s vanity, and the one book the Martians still cannot face is Mother Goose.
The book’s suggested reading includes Isaac Asimov’s “The Fun They Had”, which pairs naturally with this books-versus-electronic-media question — you can read it alongside the play and compare how each one imagines the future of reading.
How the play is staged: props, costumes and comic business
A play has no narrator to describe scenery, so its visuals live in the stage directions — and in this play those directions carry most of the comedy. Reading them is how the performance works on the page.
Think of the staging as a sequence of comic images:
- The spotlight and the easel signs open the frame. The Historian’s sign reads “Museum of Ancient History: Department of the Twentieth Century”; when the scene cuts to Mars, a second sign names Think-Tank’s rank. The signs tell the audience the location has changed with no scenery change at all.
- The historiscope is the time machine — a simple movie projector the Historian switches on, after which every scene about 2040 is a projection inside the play.
- The mirror scene establishes Think-Tank’s vanity in seconds. He asks the mirror who is most intellectually gifted, hears the flattering answer, then smacks it for being slow.
- The enormous goggles: Think-Tank puts on huge goggles to watch the probe — a visual joke about the distance and absurdity of his command.
- Oop’s hat: he opens a book, puts it on his head and announces the place may be a haberdashery — the moment books stop being mysterious objects and become whatever the Martians want them to be.
- The sandwich-eating: Oop bites the corner of a real book, chews, swallows and makes terrible faces while Omega and Iota pound his back — physical comedy that works because we know it is a book, not bread.
- The listening ritual: the crew holds books to their ears and hears nothing, ending in Oop’s loud “Not a thing!” which makes the others jump.
- The vitamins ritual — “Remove vitamins… Present vitamins… Swallow vitamins” — parodies military drill in stiff, synchronised movements.
- The Mother Goose reveal: Omega holds up the huge colourful volume so the audience reads the title before the Martians understand it — the most important visual in the play.
- The climax: Oop turns the large Humpty Dumpty picture toward Think-Tank and the audience together, so we see the resemblance at the exact moment he does.
Costume does character work before anyone speaks. Think-Tank’s egg-shaped head and robe decorated with stars and circles tell the audience he is absurd before he opens his mouth, and Noodle’s plain apprentice post beside an elaborate switchboard tells us who really runs things.
There are no diagrams or illustrations in this chapter — the staging is carried entirely by the printed directions.
Words and expressions from the play, explained in context
Plays are written to be spoken, so a play’s vocabulary is also its acting cue — a stage direction like “peevishly” tells the reader how to deliver the line. The table below goes through the terms from the book’s glossary where they actually appear, followed by play-specific expressions that do the same job.
| Term | Where it appears | What it means |
|---|---|---|
| easel | The Historian’s sign, and later Think-Tank’s | A wooden frame that holds a board or a picture |
| Zulus | The Historian’s “from ant eaters to Zulus” | An African people of South Africa — here, shorthand for absolutely everything |
| apprentice | Apprentice Noodle | A learner working under a skilled person in return for being taught |
| peevishly | Think-Tank’s first reaction to Noodle’s greeting | Irritably, in a bad temper |
| riffling | Oop with an open book | Quickly turning over the pages |
| barn | Iota’s guess about the library | A covered building for storing hay |
| haberdashery | Oop’s hat theory | A shop selling clothes, pins, cotton and small dress items |
| squiggles | Oop describing the “code” | Scrawled, messy marks — illegible writing |
| decipher | Think-Tank’s order to the crew | To find the meaning of something puzzling or hard to read |
| transcribe | “Transcribe, Omega” | The glossary defines it as writing out in full from shorthand; in the scene it means read the code out for the record |
| levity | “This is no time for levity” | Treating a serious matter without respect; lack of seriousness |
The play also builds its own special vocabulary, which works the same way:
- Era of the Book — the Historian’s name for the twentieth century, when books covered every subject and taught people how, when, where and why.
- historiscope — the Historian’s projector, which shows scenes from the past.
- salutation — a formal greeting of rank; Noodle must deliver Think-Tank’s full one every time.
- space probe — the crewed spacecraft, Probe One, sent to investigate Earth.
- communication sandwiches — Noodle’s first planted correction: the objects are for communication, not for eating.
- eye communication — the corrected idea: books are read with the eyes, not heard with the ears.
- Marsopolis — the Martian capital, where Earthlings later build a model library.
Common mistakes students make with this chapter
The biggest trap in this chapter is the time frame: the play’s frame is the twenty-fifth century, but the invasion it shows happens in 2040 — the twenty-first century. Once you fix that, most other errors come from taking the Martians’ misreadings at face value.
| Mistake | Correct rule | How to check your answer |
|---|---|---|
| “The play is set in the twenty-fifth century.” | The frame is the twenty-fifth century; the events inside the historiscope are set in 2040. | Ask who is speaking — the Historian lives in the twenty-fifth century; every scene with Think-Tank is 2040. |
| “The book stopped the invasion through its wisdom.” | No one reads it for wisdom. The Martians misread the rhymes, and the Humpty Dumpty picture happens to look like Think-Tank, so he panics and cancels the invasion. | The book wins by being misread, not understood — the panic, not the poetry, ends the invasion. |
| “Noodle directly corrects Think-Tank.” | He never contradicts him. He plants a small doubt and lets Think-Tank adopt it as his own point. | Look for his framing phrases — “a bit of data floated into my mind”, “a cloudy piece of information”. |
| “The Martians are stupid.” | They are technologically advanced — Oop has visited seven galaxies, and they have space probes, intelligence vitamins and an invasion fleet. The comedy is cultural ignorance, not stupidity. | Compare what they can do (technology) with what they cannot recognise (books). |
| “The rhymes carry secret warnings about Earth’s weapons.” | They are nonsense verses. Think-Tank reads threat into innocence because he assumes every book is a coded report. | The audience knows the real text; the gap between the two readings is the joke. |
| “The play is against books.” | It celebrates what even a book of nursery rhymes carries. The ending rewards Noodle’s humility over Think-Tank’s vanity, and the Martians are only safe once they learn to read. | Note how the play ends — with a library, not with technology. |
Exam notes: answering the questions the textbook asks
The revision target for this chapter is the set of questions NCERT itself prints against it — these are the questions the book expects you to be able to answer. The three sets test different skills, so each needs its own answering style.
| Question set | What it tests | How to answer well |
|---|---|---|
| Read and Find Out | Literal comprehension — the answers sit inside the play | Point to the exact moment in the text; a few precise lines are enough |
| Think About It | Analysis and personal response | Explain the mechanism (how or why it works), then give your own view where the question asks for it |
| Talk About It | Discussion and reflection | Connect the play to your own experience; there is no single right answer |
Read and Find Out: why the twentieth century was the Era of the Book
The Historian explains that in the twentieth century books covered everything — in her words, “from ant eaters to Zulus” — and taught people how to, when to, where to and why to. They illustrated, educated, punctuated and even decorated. In short, the book was the century’s dominant medium, which is exactly what makes the Martians’ failure to recognise one so comic.
Read and Find Out: who tried to invade Earth
The Martians of Mars, commanded by the Great and Mighty Think-Tank, tried to invade in 2040. The invasion never actually happened: the crew of Probe One landed, misread a book of nursery rhymes as a military code, and Think-Tank called the whole operation off.
Read and Find Out: Think-Tank’s guesses about books
Think-Tank’s guesses form a chain. He first calls the library a crude refreshment stand and the book in Omega’s hand a sandwich, and orders Oop to eat it.
After Noodle’s hints the objects are upgraded: communication sandwiches to be listened to, then eye communication — opened and watched, not heard. Finally he declares the marks on the page a code and orders the crew to decipher it.
Think About It: how Noodle corrects Think-Tank without offending him
Noodle manages it by never once contradicting his commander. Each correction arrives as a small, self-deprecating doubt — “an insignificant bit of data floated into my mind” and, later, “a cloudy piece of information is twirling around in my head” — which Think-Tank is free to adopt as his own idea.
The method succeeds because it respects the commander’s vanity instead of attacking it. Noodle gets the true information to the crew — that the objects are for reading, not eating — while Think-Tank keeps his belief that he is never wrong.
One revision tip: for a play, revise who says what to whom and what the stage directions reveal. Every character and humour question in this chapter comes from exactly those two things — Noodle’s phrasing toward Think-Tank, and the visual gags such as the hat, the sandwich bite and the mirror.
Revision summary: the play in eight points
The whole play in eight points, for quick revision.
- A twenty-fifth-century Historian switches on the historiscope to show the Martian invasion of 2040.
- Think-Tank, vain and “never wrong”, orders Earth invaded before lunch.
- Probe One lands in a library and the crew cannot identify books — a storage barn, then hats, then sandwiches.
- Noodle’s planted “bits of data” turn the sandwiches into a communication device, then eye communication, then a code.
- The crew reads Mother Goose, misreading each rhyme as proof of Earth’s power — silver crops, cow space attacks, high explosives.
- The Humpty Dumpty picture looks like Think-Tank, so he panics, cancels the invasion and evacuates Mars for Alpha Centauri.
- Centuries later, Earth and Mars are friends, with a model library in Marsopolis and Noodle in charge.
- The one book the Martians still refuse to read is Mother Goose — the misunderstanding that saved Earth.
Related resources and suggested reading
This listing is maintained for the 2026-27 academic session using the NCERT textbook information available to us. NCERT remains the authority for confirming the latest edition.
Where to go next: the book’s own reading list, the chapters around this one, and the official syllabus note.
The chapter ends with a suggested reading list of three stories: “Diamond Cuts Diamond” by J.H. Parker, “The Cinderella Story” by Kenneth Lillington, and “The Fun They Had” by Isaac Asimov. The Asimov story is a natural companion to this play’s books-versus-electronic-media question.
If you are revising the book in order, the previous chapter is Bholi. The Class 10 English notes hub lists the chapters in both readers, and the Class 10 hub takes you to the other subjects; for other classes and subjects, start from the notes home page.
One caution: textbook contents and the examinable syllabus are not always identical — check the current official CBSE syllabus at cbse.gov.in before deciding what to revise.
Sources and data verification
The facts on this page describe the NCERT Class 10 English textbook Footprints without Feet (Supplementary Reader), chapter 9, “The Book That Saved the Earth”, in its official editions on ncert.nic.in. This page covers only this chapter — not the other chapters of Footprints without Feet, and not the First Flight main reader.
The page is maintained for the current academic session using the NCERT information available to us. NCERT settles textbook content, editions and official PDFs; CBSE settles curriculum, syllabus and examinations.
| What the chapter holds | Count | Where it is used |
|---|---|---|
| Printed pages | 15 | |
| Official NCERT PDF | Download the chapter PDF | the chapter exactly as NCERT publishes it |
Chapter-wise notes for this subject are not published yet. The unit-wise syllabus on this page is complete and verified against the official CBSE curriculum document.
Reference: NCERT Class 10 English textbook (Footprints without Feet), chapter 9, official edition on ncert.nic.in.
Frequently asked questions
Quick answers to the questions students most often search for about this chapter.
Why did Think-Tank call off the Martian invasion of Earth?
Think-Tank called off the invasion because he panicked. Reading Mother Goose as a coded military report, he decided the rhymes proved Earth’s power — silver crops, cow space attacks, high explosives — and the picture of Humpty Dumpty, which looks exactly like him, convinced him Earth planned to capture him and Mars Central Control. He ordered Mars evacuated to Alpha Centauri.
How does Noodle correct Think-Tank without offending him?
Noodle never contradicts him. Each correction arrives as a small piece of data that floated into his own head, and Think-Tank adopts it as his own next point (“That was my next point”, “I will clarify it for you”). The true information reaches the crew while Think-Tank keeps his dignity and his “never wrong” self-image.
Why do the Martians call books sandwiches?
Because Think-Tank guesses that the library is a refreshment stand and the item in Omega’s hand is a sandwich — he assumes Earth creatures are always eating. The book even fits the description loosely: covers like two slices of bread with pages as filling. Noodle quietly refines “sandwich” into “communication sandwich”, but the food vocabulary stays for the whole scene.
What is the theme of The Book That Saved the Earth?
The main theme is the power of books and of reading: a dusty book of nursery rhymes — not an encyclopedia — saves Earth, and the Martians only become safe and friendly once they learn to read. The play also satirises vanity and blind confidence, and it leaves open the question of whether electronic media can replace books (Think About It, Q3).
Who are the characters in The Book That Saved the Earth?
There are seven characters: the Historian (museum guide and narrator), the Great and Mighty Think-Tank (the vain Martian Commander-in-Chief), Apprentice Noodle (his clever assistant), Captain Omega, Lieutenant Iota and Sergeant Oop (the three-member probe crew), and the offstage voice that answers the mirror. The engine of the play is the Think-Tank–Noodle relationship.
What is the Era of the Book, and why is the twentieth century called that?
The Era of the Book is the Historian’s name for the twentieth century, when books covered everything — “from ant eaters to Zulus” — and taught people how to, when to, where to and why to. Books were the age’s dominant medium, which is exactly why the Martians’ failure to recognise them is so funny.
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