A highly regarded biography described by Frank Sulloway as "perhaps an ideal introduction to Darwin's life and work for the nonspecialist". A psychologist by trade and the author of Attachment and Loss, Bowlby is particularly interested in Darwin's invalidism; he suggests that Darwin "developed a vulnerable personality as the result of a childhood shadowed by an invalid and dying mother and an unpredictable and often intimidating father, and that his symptoms can be understood as responses to stressful events and situations."