Geoffrey Greif, Ph.D., is a professor at the University of Maryland School of Social Work. He is the author of eleven books, including three that are co-edited, and more than 100 articles and book chapters. His recent book, Buddy System: Understanding Male Friendships, was published by Oxford University Press. It is based on interviews with more than 400 men and 122 women. A new book, Two Plus Two: Couples and their Couple Friendships (co-authored with Kathleen Holtz Deal) based on interviews with over 400 current or one-time members of couples. Other books include When Parents Kidnap: The Families Behind the Headlines (with Rebecca Hegar), Single Fathers, and Beating the Odds: Raising Academically Successful African American Males (with Freeman Hrabowski and Ken Maton). In 2007, he received the Educator of the Year award from the Maryland Chapter of NASW and in 2010 the University of Maryland Regents Award for Teaching. He received his MSW from the University of Pennsylvania and his doctorate in social work from Columbia University.