•Why it earns a slot
Treasure Island fixed the modern template of the pirate adventure, inventing or codifying the treasure map with an X, the one-legged buccaneer, and the morally ambiguous villain-hero in Long John Silver, whose complexity has kept the novel in continuous print since its 1883 publication.
Young Jim Hawkins stumbles onto a treasure map once belonging to the pirate Captain Flint, and sails with Squire Trelawney, Dr. Livesey, and Captain Smollett to recover the buried gold. The voyage is undermined from within by the ship's cook, the charismatic one-legged Long John Silver, who leads most of the crew in a planned mutiny. Through a series of bold improvisations, Jim and the loyal party outmaneuver the pirates, recover the treasure with the help of the marooned Ben Gunn, and sail home, while Silver escapes justice once more.
This distillation is written from the freely available original, which is always the better read when you have the time: gutenberg.org.