Trying to change human behaviour is an increasingly widespread phenomena. A “change industry” has developed, with beneficial objectives and strong moral standards but which uses processes that are to a large extent accepted as articles of faith. This text examines what intentional change processes essentialy are and places them in them in relation to the natural development of human change and to the question of consequences. It considers how the most important outcomes of social intervention tend to be those that were never anticipated. The principle theme of Tom Douglas’s text concerns the ignored peripheral and major consequences of intervention in the lives of people, as individuals, or as members of groups or organizations.