Community-based research challenges the traditional research paradigm by recognizing that complex social problems today must involve multiple stakeholders in the research process—not as subjects but as co-investigators and co-authors. It is an “orientation to inquiry” rather than a methodology and reflects a transdisciplinary paradigm by including academics from many different disciplines, community members, activists, and often students in all stages of the research process. Community-based research is relational research where all partners change and grow in a synergistic relationship as they work together and strategize to solve issues and problems that are defined by and meaningful to them. This chapter is an introduction to the historical roots and subdivisions within community-based research and discusses the core principles and skills useful when designing and working with community members in a collaborative, innovative, and transformative research partnership. The rationale for working within this research paradigm is discussed as well as the challenges researchers and practitioners face when conducting community-based research. As the scholarship and practice of this form of research has increased dramatically over the last twenty years, this chapter looks at both new and emerging issues as well as founding questions that continue to be debated in the contemporary discourse.