Remembered as one of science fiction's best editors, Judith Merril (1923-1997) also wrote prolifically and stands as one of the genre's central figures in America. Widely anthologized at the time, her stories have never received the attention they deserve as groundbreaking science fiction in their own right. This work offers the first comprehensive account and analysis of Merril's body of fiction, read in the context of nuclear energy, space, and what she called ""primary communication"" as the ""new frontiers"" of the 1950s. A thorough account of Merril's 50-year career, this work is a valuable reference for students of science fiction, women's biography and autobiography, women's contributions to frontier mythology, and women's activism.