Introduction Rebecca Cox and Bunmi O. Olatunji; Part I. Basic Mechanisms in Fear and Anxiety: 1. Learning mechanisms in fear and anxiety Sara Scheveneels, Yannick Boddez and Dirk Hermans; 2. Attentional bias and the anxiety disorders Ernst H. W. Koster and Anouk Vanden Bogaerde; 3. Perceptual mechanisms of anxiety and its disorders Wen Li; Part II. Transdiagnostic Processes: 4. Neuroticism/negative affectivity David Watson; 5. Anxiety sensitivity Norman B. Schmidt, Nicole Short, Ian Stanley, Nicholas Allan and Brian Albanese; 6. Disgust proneness Kelly A. Knowles and Bunmi O. Olatunji; 7. Intolerance of uncertainty Peter M. McEvoy, R. Nicholas Carleton, Kelly Correa, Stewart A. Shankman and Sarah Shihata; 8. Distress tolerance Lance M. Rappaport, Erin C. Berenz, Carl Lejuez and Roxann Roberson-Nay; 9. Experiential avoidance Fallon R. Goodman, Maria A. Larrazabal, John T. West and Todd B. Kashdan; 10. Emotion regulation Katya C. Fernandez, Amanda S. Morrison and James J. Gross; Part III. Assessment, Diagnosis, and Cultural Manifestations of Anxiety and Related Disorders: 11. Anxiety disorders Anthony J. Rosellini, Esther S. Tung and Timothy A. Brown; 12. Obsessive-compulsive and related disorders Andrew M. Kiselica and Eric A. Storch; 13. Trauma- and stressor-related disorders Daniel J. Lee, Sarah E. Kleiman and Frank W. Weathers; 14. Cultural considerations in the anxiety and related disorders Devon Hinton and Eric Bui; Part IV. Etiology and Phenomenology of Specific OCD Spectrum Disorders: 15. Specific phobia Peter J. Castagna, Marie Nebel-Schwalm, Thompson E. Davis, III and Peter Muris; 16. Panic disorder and agoraphobia Bethany A. Teachman, Miranda L. Beltzer and Alexandra J. Werntz; 17. Social anxiety disorder Arielle Horenstein, Rachel M. Butler and Richard G. Heimberg; 18. Generalized anxiety disorder Ki Eun Shin, Lucas S. LaFreniere and Michelle G. Newman; 19. Etiology of separation anxiety disorder Andrew R. Eisen and Kristin L. Toffey; 20. Selective mutism Christopher A. Kearney, Andrew Gerthoffer, Amanda Howard and Rachele Diliberto; Part V. Etiology and Phenomenology of Specific OCD Spectrum Disorders: 21. Obsessive-compulsive and related disorders Lillian Reuman and Jonathan S. Abramowitz; 22. Body dysmorphic disorder Emma Baldock and David Veale; 23. Hoarding disorder Kristin S. Springer, Blaise L. Worden and David F. Tolin; 24. Body-focused repetitive behavioral disorders Dan J. Stein and Christine Lochner; Part VI. Etiology and Phenomenology of Specific Trauma and Stressor-Related Disorders: 25. Acute stress disorder Joshua C. Morganstein, Suzanne Yang, Gary H. Wynn, David M. Benedek and Robert J. Ursano; 26. Posttraumatic stress disorder Katherine Buchholz, Zoe Feingold and Tara E. Galovski; 27. Reactive attachment disorder Kimberly Renk; Part VII. Treatment and Prevention of Anxiety and Related Disorders: 28. Anxiety disorders Joseph K. Carpenter, Kristina Conroy and Stefan G. Hofmann; 29. OCD spectrum disorders Martin E. Franklin, Simone Budzyn and Holly Freeman; 30. Trauma- and stressor-related disorders Andrew M. Sherrill and Sheila A. M. Rauch.