Birthday Letters is Hughes's account of his marriage to Sylvia Plath, which began as a love match between two gifted and ambitious young poets and ended with Plath's suicide in 1963 at the age of thirty, after Hughes had left her for another woman. The book thus makes up the untold portion of one of the great tragic love stories of our time, one so laden with myth and acrimony that at times it resembles a post-feminist Romeo and Juliet.