Knowledge about anxiety has increased exponentially since the initial publication of this classic work. This extensively revised second edition now brings the field thoroughly up to date. Part I builds on the groundbreaking conceptual framework presented in the original volume, explicating the nature of anxiety and panic in light of emotion theory, recent advances in cognitive science and neuroscience, and increasingly important findings from developmental psychology and learning. Existing chapters have been updated and restructured, and a new chapter added on etiological factors. Part II outlines what is currently known about the presentation, etiology, assessment, and treatment of each of the specific disorders. This section features chapters coauthored by Dr. Barlow and other leading experts associated with the Center for Anxiety and Related Disorders at Boston University.