Over the course of 12 chapters, this book meticulously examines the major assumptions and underpinnings associated with PTSD. The authors ask, for example, whether PTSD is a unique disorder or an amalgam of already known symptoms associated with depression and anxiety. What is the reliability of the instruments used to assess it? What is the nature of traumatic memory? The book opens with a chapter by Richard McNally—author of the excellent Remembering Trauma (1)—that emphasizes the importance of how we define a traumatic event: "The prevalence of the disorder, characterization of its psychobiological correlates, its assessment and treatment, all depend on how we define what counts as trauma," he writes. Now that the DSM defines a traumatic stressor as the experience of learning about tragedies that happen to others as long as the response involved intense fear, helplessness, or horror, we have opened up the floodgates for personal injury lawyers. The current version—a symptom of "conceptual bracket creep," as McNally calls it—has diluted the meaning of PTSD such that it becomes circular—that is, a trauma is anything that traumatizes. In the end, PTSD becomes a sprawling catchphrase that undermines the validity of diagnosis, treatment, and research. The latter, especially, depends on homogeneous study samples if it is to reveal, among other things, meaningful information about response to treatments and the biological correlates of PTSD.