Human attachment is vital for survival. The experience of attachment significantly influences social interactions, mental health, and neural processes. Recent theoretical considerations are based on the assumption that any form of attachment behavior represents an individual's adaptation to their environment, overcoming the now counterproductive distinction between secure behavior as healthy and insecure behavior as pathological. Current developments in attachment theory are comprehensively presented to the German audience for the first time in this volume by international experts. The common foundation is the empirically developed and application-oriented dynamic maturation model of attachment and adaptation (short: DMM). For each age group, attachment diagnostic procedures are outlined in their fundamental aspects. Clinical case examples illustrate the application of the DMM.