With 26 new articles and significantly revised and expanded introductory material, this revamped edition features scholarly contributions that explicate core concepts, survey contemporary issues in research, and examine ethical responsibilities toward both research participants and science itself. New additions include articles on translational and qualitative research, advances in data collection methods such as Amazon’s Mechanical Turk service and obtaining client feedback in psychotherapy, advances in mathematical and statistical modeling including single-case interventions, and new chapters addressing questionable research practices and fraud.