The article is an attempt to present holistically the key concepts of attachment theory rediscovered for its potentials. The presented concepts include: narrow definition of attachment, behavioral control system of attachment, attachment working model and patterns of attachment. The concepts are presented in the context of child attachment theory and adult attachment theory, in addition to description of the development of attachment. Concepts, as well as developmental processes are presented from the stand point of pioneers in this field (John Bowlby and Mary Ainsworth) as well as from the standpoint of their successors (Everett Waters and Malcolm West). Compacted ness of the theory, possibilities for operationalization of its key concepts and its application to empirical studies of complex psychological issues that have never been scientifically explored, makes it a very prospective theory in view of possible integration of existing research findings and initiating new research and new practices in psychotherapy, social work and work in schools. The goal of this integral presentation of attachment theory is to highlight its benefits and possibilities for understanding and research complex field of human's psychosocial functioning.