This paper describes the origin and objectives of a method of research interviewing of the whole family, provides details of the protocol and the way it is administered, and evaluates its usefulness. The method aims to elicit family interaction in a standardized fashion using principles derived from clinical interviewing. The most difficult task is training of the interviewer; he requires both the sensitivity and skill of the expert clinician and the discipline and rigour of the careful researcher. Adherence to the principles of interviewing should be monitored appropriately during research projects. The implications of the basic approach underlying the method has led to further developments in training and research interviewing.