Treatment programs are expected to change their clients. To adopt evidence-based practices to improve their therapeutic effectiveness in dealing with drug-related problems of clients, they also are expected to change themselves. The process of innovation adoption and implementation is the focus of studies included in this special journal issue. Collectively, this volume examines staff perceptions of program needs, organizational readiness for change (based on pressures, resources, staff attributes, and organizational climate), quality of workshop training, subsequent utilization of training materials, and client self-report of treatment engagement. Approximately 800 treatment programs nationwide contributed data for these studies. A standardized assessment of organizational functioning captured attributes that describe environments, settings, and staffs, and the findings are interpreted in the context of a stage-based approach to program changes. A conceptual model is used to help organize and summarize longitudinal results within the organizational context and according to implementation influences related to qualities of the innovations.