This volume examines how volunteers and non-profit programs encourage institutional change in prisons and offer individual support and services to people who are housed behind bars. Through a diverse set of chapters, including two that are co-written by current prisoners, the volume spans the United States, the United Kingdom, and Canada, and juvenile and adult facilities. The book showcases the exciting, groundbreaking, and yet often unrecognized work that the voluntary sector provides in correctional settings. Collectively, the chapters highlight beneficial practices while raising critical questions about the role of the voluntary sector in prison and reentry settings. The chapters also offer useful information about how to implement innovative prison programs that promote health, education, and peer support.