The Unbearable Lightness of BeingA young woman in love with a man torn between his love for her and his incorrigible womanizing; one of his mistresses and her humbly faithful lover these are the two couples whose story is told in this masterful novel. Kundera's first since "The Book of Laughter and Forgetting." In a world in which lives are shaped by irrevocable choices and by fortuitous events, a world in which everything occurs but once, existence seems to lose its substance, its