This volume is one in a continuing series of publications sponsored by the Banff Inter­ national Conferences on Behavioural Science. The conferences have been held each spring since 1969 in Banff, Alberta, Canada. They serve the purpose of bringing together out­ standing behavioral scientists and professionals in a forum where they can present and dis­ cuss data related to emergent issues and topics. Thus, the International Conferences, as a continuing event, have served as an expressive "early indicator" of the developing nature and composition of behavioral science and scientific application. Distance, schedules, and restricted audience preclude wide attendance at the confer­ ences. Consequently, the publications have equal status with the conferences proper. They are not, however, simply publications of the papers presented at the conference. Presenters at the Banff Conferences are required to write a chapter specifically for the forthcoming book, separate from their presentation and discussion at the conference itself. The original conference had as its theme "Ideal Mental Health Services." The policy consciously adopted at that conference, and followed ever since, was to identify for the pre­ sentation of each year's theme those behavioral researchers who could best identify the state of the art. In 1969, the conference faculty were Nathan Azrin, Ogden Lindsley, Gerald Pat­ terson, Todd Risley, and Richard Stuart. The conference topics for the first 19 years were as follows: "Ideal Mental Health Services" 1969: I.