Treasure Island is not a book with a message; instead, it is an adventure tale, pure and (except for the character of its great antagonist, John Silver) simple. Yet like some other adventure tales, Stevenson's classic novel has as its central theme one of the oldest and most universal stories. Like the folktales of young men and women who leave their homes to seek their fortunes, the myth of Jason embarking to bring home the dragon-guarded Golden Fleece, the story of Odysseus on his hazard-filled journey back to Ithaca from Troy (and the concurrent journey of his son, Telemachus, searching for his father), and the medieval romance of Perceval seeking the Grail, Treasure Island is the story of a quest.
Treasure Island has an assortment of ingredients common to quest stories. The quest hero goes on a journey, often to a strange and dangerous place, in pursuit of something valuable. On his way, he encounters one or more threshold guardians — human, animal or even supernatural — that may try to keep him from gaining his object or may only provide tests that he must pass in order to approach it; some of these may be helpful figures and others may be adversaries he must defeat. The hero is forced to test his courage, intelligence, strength, and worthiness, and sometimes encounters evidence of previous seekers who failed the tests. Sometimes, rituals (magical or otherwise) are involved, initiating the hero into esoteric secrets. The successful hero passes each test and, in the process gains some internal good — often wisdom or self-knowledge — as well as the object he sought. (You can find many modern variations of the quest theme; Hemingway's The Old Man and the Sea is a quest novel in which the questing hero brings back an object now worthless — the skeleton of the great fish he caught — but also brings home a reassurance of his own strength.) The hero of such a story is often very young and innocent, in which case the quest is also a coming-of-age adventure. Jim Hawkins' quest for Flint's treasure fits this pattern admirably, which may be one reason Treasure Island is so enduringly popular; some schools of psychology hold that the pattern is a figurative reflection of universal human experience and that such stories are thus deeply satisfying to readers at an unconscious level.
Jim's quest begins at the first appearance of Billy Bones, who is his initial helping figure, telling him in veiled terms about the map, the treasure, and the ritual of "the black spot." Black Dog and Pew are the first adversarial threshold guardians Jim encounters, and he successfully takes the map in spite of them. Silver appears at the outset to be another helper, but he is soon revealed as a more dangerous threshold guardian. By luck and stealth, however, Jim passes the difficult test of recognizing the danger Silver presents, when, from the apple barrel, he overhears Silver's revelations. Invited into the cabin to tell his story, Jim is given a glass of wine, ritually "initiating" him into the company of the men.
Jim encounters a second helping figure in Ben Gunn, who gives him information, again in veiled terms. Jim is tested a second time when the mutineers attack the stockade and a third time when he cuts the Hispaniola adrift and, on board the ship, strikes the pirates' colors. This third test so enrages the final threshold guardian, Israel Hands, that Jim is faced with his most challenging test of courage. His test of worthiness comes when, having given his word to Silver, Jim refuses to run away from the pirates' stronghold. This is the decision, made in spite of his fear, that figuratively (and perhaps literally) saves him and delivers the treasure to his friends. After he has survived that test, Jim encounters the skeleton of the man (an unsuccessful treasure seeker) whom Flint killed and left as a marker. Ben Gunn had earlier pointed out the graves where he buried the man's five companions.
However, Jim's quest is for more than treasure. This is a coming-of-age story, and Jim is a boy who at its outset loses his father (which is, in psychological terms, the first step in his becoming his own man). During his journey, Jim examines and rejects several figurative replacements: Dr. Livesey, whom he already respects but whom he must finally disobey (when Livesey urges him to break his word and run away from Silver); Squire Trelawney, who takes Jim as a sort of surrogate son but who also proves to be a fool; Captain Smollett, another authority figure, whom Jim finds too repressive; the "bad father," Hands, whose flag Jim strikes; and finally Silver himself, to whom Jim is most drawn (in the 1934 film, true in this to the book's spirit, Jim invites Silver to live with him and his mother) but whom he must ultimately reject. By the end of the novel Jim seems to have come of age entirely, symbolized, perhaps, by his recounting of the story and his refusal of further adventure.
Treasure Island has been called a "novel of greed," and certainly greed is a minor theme of the book. But the chief theme is Jim Hawkins' quest to bring home something of great value and to gain his own moral adulthood, a treasure in itself.