From its origins in the 1950s with the work of John Bowlby and Mary Ainsworth, Attachment Theory has expanded over the ensuing half century to become a central psychobiological paradigm in developmental and clinical psychology. Carefully compiled by an editorial partnership which spans both sides of the Atlantic, this new six-volume major work seeks to bring together for the first time important original papers on the subject of Attachment, making it an invaluable resource for all mental health professionals, from psychology, medicine, psychiatry, nursing, counselling, and all modalities of psychotherapy. Opening with a newly-written introductory chapter which aims to provide a contextualising map of the field, the set is carefully divided into twenty sections split over six volumes, covering a broad range of key aspects on Attachment Theory.