Psychotherapy research is undoubtedly one of the most puzzling, diverse, com- plex, controversial, and multidimensional areas tackled by clinical psycholo- gists, psychiatrists, and psychiatric social workers. The numerous theoretical, methodological, and clinical-research issues dealt with by workers in the field have increased exponentially in the past three decades. To do full justice to the area, monographs in each of the specific subareas would be warranted. In this volume, we, as editors, have endeavored to present the student and interested professional and practitioner with an understanding of the most salient issues and trends confronted by the psychotherapy researcher. In order to accomplish this task, we asked our colleagues, who are experts in their respective areas, to share their current thinking with us and with you, the read- ers. Thus, many theoretical viewpoints are represented, with none having a monopoly over the others. This is as it should be, given the data collected by clinical researchers at this time. We have also attempted to capture the excite- ment that has permeated the field in the past 30 years or so.