During the last 4 decades developments in the broad field of people_environment studies have been chequered. This is not to be unexpected as there rarely is a linear sequence in the history of any academic discipline or professional practice. Changes in subjects of research in this field have been noteable (e.g hospital wards, landscape scenery, place and the applicability gap to mention a few). Likewise the rise and fall of some research methods, including the semantic differential, checklists and photographic surveys, can be noted. In addition, there have been alternative orientations that focus on people or the built environment, and theoretical development or applied design research. An overview of the shifting emphasis attributed by contributors in this field to research subjects and methods is not meant to lead to some kind of broad consensus about the number and scope of variations or their sequence. Rather, the purpose of this symposium is to raise and debate a number of' questions that could become subjects of study in their own right. Each invited contributor to this symposium is asked to consider dimensions of constancy and change: then propose shifts in the status of research concepts and methods, and highlight some benchmarks and/or periods lacking innovation. In relation to the general theme of this IAPS 15 conference, each contributor is requested to discuss and debate whether constancy and change 'In the research agenda of this field can be related to one or more of the following: Shifts in public policy of national, regional or local governments and institutions (e.g. a concern for addressing the housing requirements of specific groups). 2. Shifts in public awareness and concern about specific issues (e.g. criminality and insecurity in urban neighbourhoods). 3. Environmental catastrophes such as Bhopal, Chernobyl, Los Angeles and Kobe. 4. International conferences including Habitat l in 1976 and Habitat 11 in 1996. 5. Political trends associated with the quest for the recognition of local, ethnic and regional identities. // In addition participants are asked to consider those innovative and well-known research subjects and methods of study that will be required in the future if this field is to contribute actively to the definition, implementation and evaluation of public policy.