Introduction to the 50th anniversary special issue on psychotherapy outcome: a return to the beginning.

Then and now, Psychotherapy is a home to those interested in expanding the research base of how and why psychotherapy is effective. In preparing to celebrate the 50th anniversary of our journal, we on the editorial board and Division 29 thought nothing could pay better homage to these issues than to reprint the seminal articles by Strupp and Eysenck on psychotherapy outcome from Volume 1. These reprinted articles will then be followed by papers from several of today's most prominent authors in psychotherapy process and outcome research who address the progress on these issues now, 50 years later, as well as provide important suggestions for how the field can move forward in future work. Again, this will be the first of several initiatives to celebrate this very special golden anniversary year!