Bowlby was interested from the beginning of his career in the problem of separation, the wartime work of Anna Freud and Dorothy Burlingham on evacuees, and the work of René Spitz with orphans.
Bowlby var interesseret fra begyndelsen af ​​sin karriere i problemet med separation, det krigstid arbejde Anna Freud og Dorothy Burlingham om evakuerede, og arbejdet i René Spitz med forældreløse børn.