The Unbearable Lightness of Being
By Milan Kundera

This is an incredible study of relationships: how they start and how they sustain themselves—or fail to. It's one of the truest things I've ever read about love and sex. The story, set in Czechoslovakia during the 1968 revolution, follows Tomas, who can't seem to engage in what's happening. Instead, he becomes involved with a number of women—while married to Tereza. Through Tomas and Tereza's relationship, Kundera shows how linked love and suffering are.