A tale of four countries: How Bowlby used his trip through Europe to write the WHO report and spread his ideas.

Attachment theory, developed by child psychiatrist John Bowlby, is considered a major theory in developmental psychology. Attachment theory can be seen as resulting from Bowlby's personal experiences, his psychoanalytic education, his subsequent study of ethology, and societal developments during the 1930s and 1940s. One of those developments was the outbreak of World War II and its effects on children's psychological wellbeing. In 1950, Bowlby was appointed WHO consultant to study the needs of children who were orphaned or separated from their families for other reasons and needed care in foster homes or institutions. The resulting report is generally considered a landmark publication in psychology, although it subsequently met with methodological criticism. In this paper, by reconstructing Bowlby's visit to several European countries, on the basis of notebooks and letters, the authors shed light on the background of this report and the way Bowlby used or neglected the findings he gathered.