Arthur Conan Doyle · 1902
About one unknown word every twelve at a 5,000-word vocabulary. Readable, but it wants support — and that band is also where readers most easily fall into flow.
Coverage = the share of words in the text you already know. The research gives two lines: 98% before independent fluent reading is realistic, 95% for the instructional level that needs support (Hu & Nation, 2000). Proper nouns are not counted as unknown — recognising that it is a name is enough; this book has 242 of them.
Comfortable from about 8,000 words, or read it with glosses. 59,370 words in total; at 150 words a minute for a non-native reader, about 6 h 36 min to finish. Average sentence length 14.5 words. Reaching 95% coverage on this book (the floor for readability) takes roughly 9,250 word families.
The opening of The Hound of the Baskervilles, word for word. Tap any word you don't know and its meaning here appears beside it — no sign-up, tap as often as you like.
Mr. Sherlock Holmes, who was usually very late in the mornings, save upon those not infrequent occasions when he was up all night, was seated at the breakfast table. I stood upon the hearth-rug and picked up the stick which our visitor had left behind him the night before. It was a fine, thick piece of wood, bulbous-headed, of the sort which is known as a “Penang lawyer.” Just under the head was a broad silver band nearly an inch across. “To James Mortimer, M.R.C.S., from his friends of the C.C.H.,” was engraved upon it, with the date “1884.” It was just such a stick as the old-fashioned family practitioner used to carry—dignified, solid, and reassuring.
“Well, Watson, what do you make of it?”
Holmes was sitting with his back to me, and I had given him no sign of my occupation.
“How did you know what I was doing? I believe you have eyes in the back of your head.”
“I have, at least, a well-polished, silver-plated coffee-pot in front of me,” said he. “But, tell me, Watson, what do you make of our visitor’s stick? Since we have been so unfortunate as to miss him and have no notion of his errand, this accidental souvenir becomes of importance. Let me hear you reconstruct the man by an examination of it.”
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Computed by Readii from the public-domain text (updated 2026-10-21), not estimated by hand. The Readii reading level is our own scale, anchored on unknown-word density; it is not the same system as Lexile or AR and does not convert directly. Unknown words are counted against a frequency list built from a large subtitle corpus, so the bands mean the same thing for any learner of English, whatever your first language. This is difficulty for a non-native reader, not a native-child reading level.