In this introduction to the special section on attachment theory and psychotherapy, the editors briefly describe the key points of attachment theory (J. Bowlby, 1969, 1973, 1980) and its relevance to psychotherapy. They then outline their criteria for the selection of papers and briefly describe their emphasis. The aim of this section is to present novel and thought-provoking research that highlights the ways attachment theory principles contribute to understanding psychotherapy practice and outcome. It was the editors' goal to ensure breadth of coverage in terms of specific problems, range of populations, and types of treatments represented and to emphasize attachment-based treatments and outcomes. ((c) 2006 APA, all rights reserved).