To Forgive is Human (1997), with Steven J. Sandage and Everett L. Worthington, Jr.
Forgiveness: Theory, Research, and Practice (2000), with Kenneth I. Pargament and Carl E. Thoresen
Handbook of Religion and Health (2001), with Harold G. Koenig and David B. Larson
The Psychology of Gratitude (2004), with Robert A. Emmons
Research on Altruism and Love (2003), with Stephen G. Post, Byron Johnson, & Jeffrey P. Schloss