Peter C. Costello, PhD, is a clinical psychologist practicing in New York City, working with individuals and couples, and an associate professor of communication at Adelphi University, where he teaches seminars in attachment theory, interpersonal communication, and adult romantic relationships. He previously served in multiple roles as a dean and an associate provost at Adelphi. He is a graduate of Swarthmore College and hold two doctoral degrees: one in clinical psychology from The Graduate School and University Center of the City University of New York (City College) and another in communication from New York University. His work combines both fields. Dr. Costello completed his clinical training at The New York State Psychiatric Institute and at the New York-Presbyterian/Columbia University Medical Center. In addition to attachment theory, his current interests include an integrative approach to psychotherapy, and in recent years he has co-chaired two international conferences sponsored by the Society for the Exploration of Psychotherapy Integration. He also serves on the editorial board of the newly launched journal of the Unified Psychotherapy Project.