The Idiot by Fyodor Mikhailovich Dostoyevsky

Twenty-six-year-old Prince Lev Nikolayevich Myshkin returns to Russia after spending several years at a Swiss sanatorium. Scorned by the society of St. Petersburg for his trusting nature and naivety, he finds himself at the center of a struggle between a beautiful kept woman and a virtuous and pretty young girl, both of whom win his affection. Unfortunately, Myshkin's very goodness precipitates disaster, leaving the impression that, in a world obsessed with money, power, and sexual conquest, a sanatorium may be the only place for a saint.(Wikipedia)