ByTheBook

Learn by the book

Classic stories adapted to your reading level. At the lower levels, the language simplifies — but sentence by sentence, the author's voice comes back. Until the original is yours.

Edgar Allan Poe The Tell-Tale Heart Horror
A1 A2 B1 B2 C1 Original
12 min read time
1843 published
Start Reading

A nameless narrator tries to convince the reader of his sanity while describing a murder he committed.

iOS
O. Henry The Last Leaf Drama
A1 A2 B1 B2 C1 Original
15 min read time
1907 published
Start Reading

A young artist lies ill, convinced she will die when the last ivy leaf falls from the vine outside her window.

Android

Coming mid-2026

Every sentence, rewritten for your level

Each sentence is adapted independently by Gemini — vocabulary simplified, grammar restructured, validated against the CEFR-J vocabulary profile and a grammar framework of 45+ structures. At lower levels the voice simplifies; as you climb, the author's style comes back.

The Last Leaf
The Last Leaf O. Henry

That was1 in May. In November a cold, unseen stranger, whom the doctors called2 Pneumonia, stalked3 about the colony, touching one here and there with his icy fingers.4 Over on the east side this ravager strode boldly, smiting his victims by scores,5 but his feet trod slowly through the maze of the narrow and moss-grown "places."

1 Past simple (A1)2 Non-restrictive relative (B2)3 Past simple (A1)4 Present participle (B2)5 Present participle (B2)
Vocabulary
The Tell-Tale Heart
The Tell-Tale Heart Edgar Allan Poe

When I had waited a long time, very patiently, without hearing him lie down,1 I resolved2 to open a little a very, very little crevice in the lantern. So I opened3 it you cannot imagine4 how stealthily, stealthily until, at length a simple dim ray, like the thread of the spider, shot from out the crevice and fell full upon the vulture eye.5

1 Subordinate clause (A1)2 Past simple (A1)3 Past simple (A1)4 Modal: can (A1)5 Time clause (A2)
Vocabulary
The Masque of the Red Death
The Masque of the Red Death Edgar Allan Poe

Towards the close of the fifth or sixth month of his retreat, while the plague raged most furiously abroad,1 Prince Prospero entertained2 his thousand friends at a masked ball of the most unusual3 elegance.

1 Time clause (A2)2 Past simple (A1)3 Superlative (A1)
Vocabulary
The Gift of the Magi
The Gift of the Magi O. Henry

So now Della's beautiful hair fell1 about her. It waved2 and shone3 like a waterfall of brown waters. It reached4 below her knee and made5 itself almost a garment for her. And then she did6 it up again, nervous and quickly. She paused7 for a moment and stood8 still while a tear or two splashed on the worn red carpet.9

1 Past simple (A1)2 Past simple (A1)3 Past simple (A1)4 Past simple (A1)5 Past simple (A1)6 Past simple (A1)7 Past simple (A1)8 Past simple (A1)9 Time clause (A2)
Vocabulary
Chickamauga
Chickamauga Ambrose Bierce

The child moved1 his little hands and made2 wild, uncertain signs. He made3 a number of terrible cries something between the noise of a monkey and the cry of a turkey a frightening, ugly sound, the language of a dark creature. The child could not hear4 or speak.5

1 Past simple (A1)2 Past simple (A1)3 Past simple (A1)4 Modal: could (A2)5 Modal: could (A2)
Vocabulary
The Interlopers
The Interlopers Saki

Ulrich did not speak1 for a few minutes. He listened2 to the tired cry of the wind. A new idea slowly grew3 in his brain. It got4 stronger every time he looked5 across at the other person. That person fought6 so hard against pain. Ulrich himself was7 also in great difficulty. His old deep hate seemed8 to be going away.

1 Past simple (A1)2 Past simple (A1)3 Past simple (A1)4 Past simple (A1)5 Past simple (A1)6 Past simple (A1)7 Past simple (A1)8 Past simple (A1)
Vocabulary

Every text adapts to you

Not one fixed level per story. Within a single reading session, each sentence is served at a different difficulty — most at your comfort zone, some a step above, a few below. The mix keeps you reading without getting stuck.

Johnsy’s eyes were open wide. She was looking out the window and counting counting backward. “Twelve,” she said, and a little later “eleven”; and then “ten,” and “nine”; and then “eight” and “seven,” almost together. Sue looked solicitously out the window. What was there to count? There was only a bare, dull yard to be seen, and the blank side of the brick house twenty feet away. An old, old ivy vine, gnarled and decayed at the roots, climbed half way up the brick wall. The cold breath of autumn had stricken its leaves from the vine until its skeleton branches clung, almost bare, to the old bricks. “What is it, dear?” asked Sue. “Six,” said Johnsy, in almost a whisper. Three days ago there were almost a hundred. It made my head hurt to count them. But now it’s easy. There are only five left now.”
Comfort 79% B2 71% · B1 8%
Stretch 14% C1 14%
Reinforcement 7% A2 7%

Every word, explained in context

Tap any word while reading to see its translation and a short explanation. Not a dictionary lookup — Gemini writes each gloss for that specific sentence, in your native language, explaining what the word means in context.

An old, old ivy vine, gnarled and decayed at the roots, climbed half way up the brick wall.
ivy vine
enredadera de hiedra
'Ivy' es una planta trepadora. 'Vine' es cualquier planta que crece trepando. Juntas, describen la planta que cubre la pared.
Same sentence
gnarled retorcido, nudoso
Describe algo viejo y torcido, como las ramas de un árbol muy antiguo.
decayed podrido, descompuesto
at the roots en las raíces
climbed half way up trepó hasta la mitad

What makes it different

Adaptive Reading

Every sentence at the right difficulty. Our algorithm mixes levels within a single reading session — mostly at your comfort zone, with some stretch and reinforcement woven in.

Progressive Journeys

Spaced repetition meets reading. The app recommends when to re-read and what to try next, tracking your path from A1 to the original text.

Audio at Every Level

Each level has its own narration generated by Gemini 2.5 Flash TTS, with tempo adapted to difficulty. Slower at A1, natural pace at the original. Word-by-word highlighting follows along.

Faithful Adaptations

Not summaries. Real adaptations. Gemini rewrites each story at 5 CEFR levels. A validation pipeline then checks every sentence against the CEFR-J vocabulary profile and 45+ grammar structures. The original is always the reference point.

The reading loop

Your level isn't fixed. It evolves with every story you read.

1

Assess

A quick placement determines your reading level. Not just "B1", but a precise point on the scale.

2

Read

The adaptive mixer serves each sentence at the right difficulty. Comfort, stretch, and reinforcement woven together.

3

Respond

After each reading session, a quick survey: "How was this for your level?" Your feedback calibrates the system.

4

Grow

The system adjusts. Re-read at a higher mix, or move to a new story. Your level evolves with every page.

The story behind ByTheBook

I grew up reading in Spanish — Mann's The Magic Mountain, Walser's Jakob von Gunten, Auster's The Book of Illusions, King's Hearts in Atlantis, Salinger's The Catcher in the Rye — all in translation. At some point I wanted to read the originals. Poe's Tell-Tale Heart, where every sentence tightens like a knot and you can feel the narrator losing his mind through the rhythm alone. Sterne's Tristram Shandy, with its tireless digressions that somehow say more by never getting to the point. Beckett's Watt, that spare, relentless prose that keeps interrogating its own language as if words themselves were suspect. O. Henry's The Last Leaf, where the whole weight of the story hangs from a stem about to break.

But the gap between "I can hold a conversation in English" and "I can actually read these" was enormous. Textbooks taught me grammar and vocabulary — genuinely useful, but not enough to sit through Sterne's digressions within digressions. Graded readers got me closer, and I'm grateful they exist, but they had to simplify so much that the thing I was chasing — the author's voice, the way a sentence feels — wasn't there anymore.

"The pleasure of the sentence is to a high degree cultural. We are playing with an exceptional object, whose paradox has been articulated by linguistics: immutably structured and yet infinitely renewable: something like chess."

Roland Barthes, The Pleasure of the Text

I think there's something irreplaceable about reading literature in its original language — not as an exercise, but as a way to understand how someone else thinks and writes. I built ByTheBook because I wanted something that would walk me there, not drop me in the deep end. At the lower levels, a lot gets lost — it has to. But sentence by sentence, the author's style comes back: the irony, the rhythm, the phrasing. By the time you reach the original, you can actually read it — not because you skipped the hard parts, but because you grew into them.

Every story in ByTheBook is a public domain work — written by authors who gave us some of the most extraordinary prose in the English language. Adapting their writing is something I don't take lightly. Poe, O. Henry, Saki, Bierce — each one had a voice so distinctive that even a single sentence can be enough to recognize them. This project exists because of what they left behind, and the least we can do is try to bring more readers to their work, not away from it. The adaptations are always a bridge, never a replacement. The original is always the destination.

None of this would be possible without Gemini. It adapts each sentence to the right level, writes the contextual glosses, narrates every story with Gemini 2.5 Flash TTS, and detects grammar structures so the validation pipeline can enforce CEFR constraints. It's not magic — behind it there are carefully crafted prompts, a vocabulary profile of 8,000+ words, and a grammar framework with 45+ structures. But the fact that a single model can handle adaptation, explanation, and narration with this level of quality is what makes the whole thing work.

Victor Albertos Founder & CTO · 12+ years in software engineering Full-stack engineer: backend, Android, DevOps. Currently CTO at Significo (healthcare tech). Creator of open source libraries with 4,000+ GitHub stars (RxCache, ReactiveCache, BreadcrumbsView). Deep Learning & Data Science nanodegrees (Udacity). Based in Valencia, Spain.