“I've always wanted to write,” declared John Fowles in a 1964 essay, “(in this order) poems, philosophy, and only then novels” (published in Wormholes: Essays and Occasional Writings, 1998). Though he has established a reputation as a philosopher—both a philosophical novelist and, in The Aristos: A Self-Portrait in Ideas (1964), an accomplished existentialist thinker—and has published books of essays, naturalist writing, and one book of poetry, it is as a novelist that Fowles is firmly established in the first rank of postwar English authors. His six novels, published over two decades, have brought him a combination of popular success and critical and intellectual acclaim that is almost unprecedented in his time. His success in the marketplace derives from his great skill as a storyteller. His fiction is rich in narrative suspense, romantic conflict, and erotic drama. Remarkably, he manages to sustain such effects while, as an experimental writer testing...