Introduction WE HAVE HAD the opportunity to study the basic family constellation in six cases of incest. This paper has grown from our clinical observations and a series of staff discussions of these cases. Members of the disciplines of psychiatry, social work, and psychology participated in the study. Our theoretical frame of reference combines individual with family dynamics, and our perspective on incest derives from several sources. We were gratified to discover the compatibility of these varied frames of reference in contributing to our understanding of the clinical data. Incest has been defined by Levi-Strauss1and Slater2as "overt sexual intercourse occurring between members of a group who are not permitted by their society to marry." Since each of our six cases involved the father and daughter of a nuclear family, our findings and conclusions must necessarily be restricted to this special class of incest. Past contributions