Marc J. Diener, PhD is an Associate Professor in the Clinical Psychology Doctoral Program at Long Island University—Post, and he maintains an independent clinical practice. He earned his doctorate in clinical psychology from Adelphi University, and he trained at both Bellevue Hospital and St. Luke's Roosevelt Hospital Center. He completed a postdoctoral fellowship at The Addiction Institute of New York/St. Luke’s Roosevelt Hospital Center. Prior to joining the faculty at Long Island University—Post, he was a faculty member at the American School of Professional Psychology, Washington, DC. He has published widely, including peer-reviewed journal articles, book chapters, and other publications. He serves as a consulting editor for several journals, and his professional presentations include peer-reviewed and invited talks. He is a Fellow in the Division of Independent Practice of the American Psychological Association. In his clinical practice, he provides psychological testing, individual psychotherapy, and supervision/consultation.