Jim Hawkins, the young narrator, is neither a stock character nor a personality type. His actions throughout the book tell readers a few things about him: He tries to warn Billy Bones of Black Dog's arrival; he fears Pew but goes back to the inn with his mother; he fantasizes (he tells readers) about the upcoming voyage; he bullies the boy who has taken his job at the inn upon realizing that he is not indispensable there; he takes two extremely foolish chances on impulse, when he leaves the ship and later leaves the stockade (part of his function in the novel is to do these things, although his greater function is to tell the story). He fights for his life with Israel Hands on the Hispaniola, and kills Hands by accident (but he was ready to kill him on purpose; about this he says nothing). He occasionally bursts into tears, and once, witnessing Silver's murder of the crewman Tom, nearly faints. Throughout, he reports every incident faithfully, revealing very little about his own feelings. At the end, he says he wants no more of Treasure Island, but he does not explain why. About all you can glean from all this is that Jim is a smart, goodhearted, and relatively courageous adolescent boy, one who is writing a report and not baring his soul. Thus Jim is entirely believable as a character — the world is full of people about whom you know no more than you do about Jim — but he is almost entirely closed. Or perhaps one should say he is almost entirely open — to the reader's imagination. You can put yourself in Jim Hawkins' place and can easily identify with him, because there is no evidence of anything in this character that may distance readers from him. This is the book's great strength as a narrative that engages readers and holds them spellbound. You see all of the action through Jim's eyes, and his openness allows you to see it through your own. Jim as narrator is the chief reason you do not question the merely surface description of other characters, for the others are seen through his eyes. Jim tells readers what they do and say but very rarely what he thinks or feels about what they may think or feel. Treasure Island is an adventure story and not a novel of character, because Jim Hawkins is its narrator and Stevenson chooses to have him tell it as he tells it. He is a character whom his author chooses not to reveal.
But Jim's strength as an engaging, open narrator leaves him a rather flat, predictable character. Nothing he does surprises readers, who are prepared even for his impulsive actions by the early reckless curiosity he displays in rising from his hiding place to see what the pirates are doing at the inn. There is no inner conflict for Jim; he is never tempted to join the mutineers. The same can be said of almost every other character in the book. They're all either obviously "good" or obviously "bad" people — even Ben Gunn, who has recently switched sides — which makes Treasure Island to that extent a pure action adventure, a story of how the good characters by luck and fortitude defeat the evil ones.