4 h 53 minAudiobook15 minSummaryRead it, hear it, the 15-minute summary, and print and large print at cost
Audiobook edition · 4 h 53 minPaperback · 6 × 9 in · printing soonHardcover · 6 × 9 in · printing soonAbout this book
A vanished father, a yearly pearl, and an unknown sender draw Sherlock Holmes into a dangerous hunt for treasure.
Mary Morstan brings a strange story to Baker Street: her father has disappeared, and someone sends her a pearl each year. Sherlock Holmes welcomes the puzzle. With Dr John Watson beside him, he follows her case into dark London streets, where a family secret opens onto an old crime.
In Arthur Conan Doyle’s The Sign of the Four, a footprint, a stain, and a watch can become steps in a chain of reasoning. Watson tells the story as the search gathers pace, linking hidden riches to betrayal in India. Treasure promises wealth, but fear and greed surround those who seek it.
What you’ll discover
- Small clues, sharp reasoning Watch Holmes turn overlooked details into questions that carry the investigation forward.
- London after dark Follow the trail through fog and lamplight toward a tense pursuit on the Thames.
- Watson's warmer view Share the case with an honest narrator whose interest in Mary becomes personal.
- Treasure with a cost Explore how the riches of Agra bind people through greed, guilt, and old betrayals.
- An unlikely tracker Meet Toby, the mongrel whose keen nose helps trace a trail through London.
Who will love it
Readers who love puzzles solved through close observation, foggy Victorian London, buried treasure and river chases will enjoy this book, along with fans of fast mysteries with a touch of romance.
What’s inside
The key ideas, in the 15-minute summary
- Holmes needs a problem, and Miss Morstan brings one
- A letter, a map, and a night ride south
- A locked room, a thorn, and tiny footprints
- A dog, a barrel, and a trail to the river
- Street boys, a disguise, and the hunt begins
- Greed poisons everyone who touches the treasure
- Cool reason and warm feeling pull against each other
- Watson tells it, and London is the stage
Who’s who
- Sherlock HolmesA consulting detective who reads small facts like print and craves hard problems, since idleness drives him to cocaine.
- Dr. WatsonA retired army surgeon and Holmes's friend, who narrates the case and grows fond of the client, Mary Morstan.
- Mary MorstanA calm young governess whose father vanished years ago, and who receives a pearl every year from an unknown sender.
- Thaddeus SholtoA twitchy, nervous patron of the arts who wants to give Miss Morstan her fair share of the treasure.
- Athelney JonesA confident Scotland Yard inspector who trusts common sense and hard facts and arrests the wrong man.
- Jonathan SmallA wooden-legged former convict whose name is on the old plan, and who wants what he believes is owed him.
- TobyA clumsy mongrel with an astonishing sense of smell, borrowed from a taxidermist to follow a creosote trail.
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- Hardcover
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- Large print paperback
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- Large print hardcover
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The Sign of the Four
by Arthur Conan Doyle · 1890
A pearl comes by post each year, then a letter sends Mary Morstan to a theatre pillar at seven o'clock.
Medium level2–5 hours to readEnglish
Excellent
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In short
Sherlock Holmes rolls up his sleeve and injects a seven percent solution of cocaine, because London has given him nothing to think about. His friend Dr.
The Sign of the Four at a glance
- Reading time
- About 2 h 45 min2 h 10 min fast, 3 h 20 min slow
- Length
- 39,600 words12 chapters
- Pages
- 120 pages181 in large print
- Library level
- Medium longer sentences, everyday words
- First published
- 1890by Arthur Conan Doyle
Reading time at 238 words a minute (fast 300, slow 200). How long the classics take to read · Updated
From the 15-minute summary · Key idea 1
Holmes needs a problem, and Miss Morstan brings one
The book opens on a bored man. Holmes has no case, so he takes his syringe from a neat morocco case and injects cocaine. Watson warns him that the drug will wear down the very brain he values. Holmes answers that his mind rebels against dullness, and that he wants work, not medicine.
Then he shows what he means by work. He is the only unofficial consulting detective in the world. He also separates two skills. Observation sees red earth on Watson's shoe. Deduction adds that Watson sent a telegram, since he had stamps and postcards but had written no letter.
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Also in the Sherlock Holmes Book Set: Four Classic Mysteries
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- 15-minute summary
- The key ideas of the whole book in about 15 minutes. A good first look, or a refresher.
Details
- First published
- 1890
- Language
- English
- Reading time
- 3 h 10 min
- Level
- Medium level
Cite this edition
Doyle, Arthur Conan. The Sign of the Four. Library of Alexandria, 2026, libraryofalexandria.com/products/the-sign-of-the-four.
Doyle, A. C. (2026). The sign of the four. Library of Alexandria. https://libraryofalexandria.com/products/the-sign-of-the-four (Original work published 1890)
Doyle, Arthur Conan. The Sign of the Four. Library of Alexandria, 2026. https://libraryofalexandria.com/products/the-sign-of-the-four.
@book{doyle2026sign,
author = {Doyle, Arthur Conan},
title = {The Sign of the Four},
publisher = {Library of Alexandria},
year = {2026},
url = {https://libraryofalexandria.com/products/the-sign-of-the-four},
note = {First published 1890}
}
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What is The Sign of the Four about?
It follows Sherlock Holmes and Dr. Watson as they help Mary Morstan, whose father vanished and who receives a pearl each year. The case leads to a murdered man, a stolen treasure chest and a hunt along the Thames.
What does the sign of the four mean?
It is a mark of four crosses drawn with four names on an old map. It stands for a pact among four men, and it later appears on a card left at a crime scene.
Is The Sign of the Four a sequel to A Study in Scarlet?
Yes, it is the second Sherlock Holmes novel, published in 1890. It stands on its own, though Watson mentions the first case and Holmes teases him about the way he wrote it up.
The author
Arthur Conan Doyle
1859–1930 · British detective novelist
Arthur Conan Doyle was a British writer and physician born in Edinburgh in 1859. He practised medicine in England and wrote novels, short stories and histories. His Sherlock Holmes stories began with A Study in Scarlet in 1887. He also wrote The Lost World in 1912. He died in Crowborough, England, in 1930.
More by Arthur Conan Doyle
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