There are no more profound influences on our lives than those we choose to love and those who choose to love us. Doris Grumbach's frank and moving new novel, The *Book of Knowledge*, illustrates this truth as it plays out in the lives of four characters whose departures from the sexual norm will alter their fates in the deepest ways. The four are Caleb and Kate Flowers, brother and sister; Lionel Schwartz; and Roslyn Hellman. They meet in the placid seaside town of Far Rockaway, New York, in the summer of 1929, as the country stands on the brink of great financial disaster and they are about to enter puberty. Raised by their widowed mother, Emma, in self-sufficient isolation, Kate and Caleb's mutual absorption with each other will by subtle degrees turn incestuous and mark their lives indelibly. Roslyn will discover during a long and finally traumatic stay at summer camp that her intellectual hauteur is no defense against disappointment and sudden self-discovery. And years later, at Cornell, Lionel and Caleb will begin a passionate affair in which their homosexuality is acknowledged by themselves for the first time. Meanwhile Kate will pine away in Far Rockaway for Caleb, her lost and only love. Decades before "coming out" was even thinkable, let alone doable, these four characters must wrestle in the shadows with their deepest feelings and fears. With a skill that has made her one of the country's most admired novelists, Doris Grumbach takes material that not very long ago would have been considered shocking, even perverse, and shows us the human costs, in loneliness and despair, that our restrictive sexual mores exacted on those who were different. *The Book of Knowledge* is her most accomplished and, in its devastatingly quiet way, most tragic novel yet.