Being at once highly educated yet appallingly ignorant, I knew the book had a good reputation, but in the manner of Paul Coehlo's The Alchemist has a following. Anticipating some semi-mystic wittering common among the more esoteric offerings of the 1960s and 70s, The Magus took those expectations and fed them into the shredder. It also turns out that The Magus is pretty impossible to review.
What Fowles has given us is a novel that plays with coming-of-age tropes, tragic love affairs, and detective stories, but also throws in Greek myth, psychoanalysis, Nazis, Shakespeare, hypnosis. It's difficult to say anything that doesn't spoil the book in some way, except to say the whole thing is a rabbit hole that draws you in deeper and deeper. Once you're satisfied with one explanation for the goings ons, it's upended and the mystery rewrites itself. In this respect it reminded me a bit of Lost, without losing itself in the complexity of the plot. In literature, the nearest it comes to is probably Foucault's Pendulum by Umberto Eco, though Fowles' novel is more accessible and satisfying.
Because it questions the extent to which one can rely on one's own perceptions, sense-making, and intentions, The Magus has lazily been described as a postmodern novel. This is a bit of retrospective padding. Given its concerns with the mind and the unconscious, and its darting twists and unexpected - and sometimes absurd - set-pieces, The Magus is a culmination of surrealist themes the postmodern later drew upon.
Call me a proselytiser, but it's not often a novel really grabs me. This one has. Get it. Read it.