Book excerpt: The Handbook of Research Methods in Abnormal and Clinical Psychology presents a diverse range of areas critical to any researcher or student entering the field. It provides valuable information on the foundations of research methods, including validity in experimental design, ethics, and statistical methods. The contributors discuss design and instrumentation for methods that are particular to abnormal and clinical psychology, including behavioral assessment, psychophysiological assessment and observational methods. They also offer details on new advances in research methodology and analysis, such as meta-analysis, taxometric methods, item response theory, and approaches to determining clinical significance. In addition, this volume covers specialty topics within abnormal and clinical psychology from forensic psychology to behavior genetics to treatment outcome methods.