This introduction to the two papers that follow by Anne Alvarez and Edna O'Shaughnessy is a revised version of the introduction to the ACP Study Day in February 2005 on ‘Integration, Unintegration, Disintegration’, at which Alvarez and O'Shaughnessy had presented and which the author had chaired. The background to the debate is given in terms of how the ACP Study Day itself came about, and the central theme is highlighted in terms of the question of whether unintegration is conceived of as a normal stage of development or only a temporary state of mind in response to catastrophic anxieties. Brief clinical material from a case supervised by the author is discussed in order to elaborate this central question.