Interface edited by Dolores HaydenOver half a century, Peter Marris worked as a sociologist, planning consultant, and professor in England, Kenya, Nigeria, and the United States. Marris began his social research in the East End of London and went on to study family structure, housing patterns, entrepreneurship, and redevelopment in many urban contexts across the world. Throughout his long career he extended his analysis of how the powerful push uncertainty onto the powerless. For an audience in urban planning, he demonstrated how to analyze the personal societal consequences of complex public decisions. For an audience in sociology, psychiatry, and psychology, he connected theories of loss and attachment to broader questions of urban policy. He taught students at MIT, UC Berkeley, UCLA, and Yale to think about these challenging issues.Section I, Life and Work of Peter Marris, begins with a biographical essay by Dolores Hayden of Yale University, who explores how his many books and articles advanced understanding of the complex intersection of private life and public life. This is followed by Charles Hoch's essay, Planning Theory and Social Change. Hoch, from the University of Peter Marris