Letters from ainsworth: contesting the 'organization' of attachment.

As Main (1999) noted in her obituary for Mary Ainsworth, 'she was interacting weekly by letter and manuscript with her mentor and friend, John Bowlby, and their academic correspondence formed an important part of her, and implicitly our, life.' These letters of Ainsworth to John Bowlby during the 1980s, available in the Wellcome Trust Library in London, contain valuable reflections on the work of her pupils to extend her system of classifying infant behaviour in the Strange Situation Procedure. Mary Main proposed a D classification and interpreted such behaviour as a breakdown in an ABC strategy caused by a conflict between a disposition to approach and flee from the caregiver. Patricia Crittenden extended the subtypes of A and C, using a developmental model of information processing, and observed that they could be used together in A/C combinations. These letters offer insight into Ainsworth's intellectual rationale for encouraging both Main and Crittenden in their conflicting endeavours.