As we approach the second edition of this textbook, we reflect on the fact that we published the first edition only two years ago. When the first edition was introduced, we wondered whether instructors and students would perceive the need for a new textbook, and we were pleased to find so many people who resonated to the scientist-practitioner approach. Abnormal psychology remains one of the most popular courses among undergraduate students as national and world events drive us to try to understand human behavior and the forces that shape and act on it. What factors drive someone to take a gun and shoot a member of the United States congress? How could a celebrity, who seemingly has everything—wealth, family, fame—shoplift a $50.00 item of jewelry? The answers to these questions do not come easily as we see simplistic answers such as “the measles vaccine causes autism,” a theory first accepted and now completely discredited