Book excerpt: Attachment theory is influencing how we understand interpersonal relationships and how psychotherapy can help facilitate change for those struggling in relationships. More recently, researchers and clinicians have applied attachment theory to group treatment, one of the most effective forms of psychotherapy to address interpersonal difficulties. This book highlights some of the bridges between attachment theory and contemporary approaches to group treatment. In addition to applying attachment theory to innovative treatments, each chapter addresses a specific way in which attachment impacts the members’ capacity for empathy and perspective taking; the development of cohesion in the group; the automatic fight-flight response during group interactions; members’ ability to tolerate diversity; and the leaders’ capacity to foster safety within the group. This book will help group leaders gain a richer understanding of attachment theory and attachment based techniques that will ultimately benefit their groups. This book was originally published as a special issue of the International Journal of Group Psychotherapy.