[Cross-posted from New Books in Psychology] Identical twins, separated at birth, raised in different families, and reunited in adulthood. In 1979, psychology researchers in Minnesota found some twins who had been reunited after a lifetime of separation, and brought them in to participate in a research study. And so began the Minnesota Study of Twins Reared Apart. At the time, psychology leaned heavily toward the nurture side of the nature-nurture debate. The twins provided unique information about the role of genes and environment in human development. Over the twenty years of the study, massive amounts of data about the twin pairs were collected about intelligence, personality, medical traits, and many other aspects of development. The results changed our understanding of how we become who we are in adulthood. In her book, Born Together-Reared Apart: The Landmark Minnesota Twin Study (Harvard University Press, 2012), Dr. Nancy Segal describes the history of the controversial Minnesota Study of Twins Reared Apart, as well as the results of the study and case examples of these fascinating twin pairs. Her book recently won the prestigious William James Book Award from The American Psychological Association.