The purpose of the articles in this volume is to present the current state-of-the-art in conceptualization and research on program quality in substance dependency treatment. One of the topics addressed is how treatment program outcomes should be defined. In this regard, one article discusses the emergence of evidence-based medicine as the primary criterion of quality and describes the most common models for characterizing drug dependence and its treatment. Another article describes a wide range of performance measures that are relevant to substance dependency treatment programs. A second topic considered in some of the articles is how research-based quality treatment can be disseminated to the field. Articles on this topic cite the lack of effective communication and interaction between researchers and practitioners. The general thrust of these articles is that greater attention should be given by researchers to increasing the external validity of evaluation studies, while maintaining scientific rigor and facilitating the use of psychotherapy technology tools. The authors believe this would help foster the needed collaboration between researchers and practitioners. Other topics discussed in the articles of this volume are the role of accreditation models in promoting treatment quality, the conceptualization and measurement of the treatment process, and guidance on program/treatment quality from the research base. 7 references