The Temple Of Dawn by Yukio Mishima
Mishima's literary powers are on full display in his penultimate novel that is a meditation on reincarnation and Buddhist philosophy.
Honda, a brilliant lawyer and man of reason, is called to Bangkok on legal business, where he is granted an audience with a young Thai princess - an encounter that radically alters the course of his life. He is convinced she is a reincarnated spirit, and undertakes a long, arduous pilgrimage to the holy places of India, where, in the climactic scene, he encounters her once more, only to have his newfound beliefs shattered and his life bereft of all meaning.