This invited set of reflections upon the research carried out under the auspices of a school of social work is part of a series featuring research centers. It reflects 25 years of scholarly work related to both public and nonprofit human service organizations at the only university-based research center in the United States devoted to research on the management of human service organizations. Organized in the predefined categories of center history, structure, past projects, and current projects, it features current and past research in the areas of welfare services, child welfare services, adult and aging services, organizational support for evidence-informed practice, sustainability of nonprofits, international human services, and practice research methodology. Dedicated to the principles of team science by including graduate students, postdoctorate fellows, and consulting researchers, the Mack Center features the processes of practice research in which practitioners play a major role in the research process.