This historic correspondence between Bromberg and Gill reflects a number of changing ideas about therapeutic regression from two different theoretical traditions. Bromberg's seminal paper is part of his project to highlight how interaction related to change must always involve the analyst's appreciation of the need to preserve self-stability in the attempt to reconfigure experience. The correspondence reflects elements of Gill's evolving efforts to move from a view of the analyst as an observer to that of a participant observer. This discussion highlights the ways that the two understood each to be adding missing elements to his previous theoretical scaffolding.