Today is Robert Louis Stevenson‘s birthday (1850-1894). Even Google is celebrating, as you can see from its Treasure Island-themed link icon (above).
Frye in “Third Variation: The Cave” in Words with Power:
In most descent mythis there is some formidable enemy — Minotaur or dragon or demon like Asmodeus — to be fought and overcome, and frequently this enemy is blocking the goal of the descent. The goal is often, in popular romance especially, a treasure of gold or jewels, as in Treasure Island or Tom Sawyer or Poe’s Gold Bug. . . The type of society that searches for such treasure is an instensely selective one. In popular literature the searchers may be boys or antisocial groups (pirates and the like) that boys find it easy to identify with. The standards of admission often reverse those of more conventional societies. . . Often the dragon-guarded hoard is a metaphor for some form of wisdom or fertility that is the real object of descent. (CW 26, 203)