Few theories have influenced Western thought as much as psychoanalysis has, even in the absence of empirically confirmatory evidence. The raw data of psychoanalysis are the words and actions of the patient and their interpretation by the analyst. The psychoanalytic session has excluded other observers and, until very recently, even a tape recorder. The only evidence of what transpired between patient and therapist was supplied by the memories, accounts, and records each of them might havekept. Thedegree to which each could be objective and veridicalin recording the events in treatment is not known, but given the intense, emotional nature of the clinical interaction, it is likely thatsystematic distortions, omissions, and inventions occurred. Various writers havecalled attention to the lack of scientific investigation of psychodynamic propositions. This seriesis intended to describe the best and most current experimental work inspired by psychoanalytic theories. A scientific theory is expected to generate data that will force it to be revised and ultimately discarded. Most of the experiments reported in this series point to instances where the theory must be modified to fit the data more exactly.