In this symposium, disciplinarity refers to the specialisation of academic disciplines that became strong during the 19th century. Multidisciplinary refers to research in which each specialist remains within her/his discipline and contributes using disciplinary concepts and methods. Interdisciplinary contributions can be interpreted as the bringing together of disciplines which retain their own concepts and methods that are applied to a mutually agreed subject. In these studies one contributor will usually co-ordinate the research process and seek integration. Interdisciplinarity can be considered as the mixing together of disciplines, whereas transdisciplinarity implies a fusion of disciplinary knowledge with the know-how of lay-people that creates a new hybrid which is different from any specific constituent part. This interpretation means that transdiciplinarity is not an automated process that stems from the bringing together of people from different disciplines or professions. In addition, it requires an ingredient that some have called “transcendence”. This implies the giving up of sovereignty over knowledge, the generation of new insight and knowledge by collaboration, and the capacity to consider the know-how of professionals and lay-people. Collectively, transdiciplinary contributions enable the cross-fertilisation of ideas and knowledge from different contributors that leads to an enlarged vision of a subject, as well as new explanatory theories. Transdisciplinarity is a way of achieving innovative goals, enriched understanding and a synergy of new methods. All these are essential if our current understanding of the interrelations between health and residential environments is to be improved. Multidisciplinarity, interdisciplinarity and transdisciplinarity are complementary rather than being mutually exclusive. It is important to stress this complementarity because without specialised disciplinary studies there would be no in-depth knowledge and data. The interrelations between these approaches ought to be more systematic than they have been in general, and in studies of housing and health, in particular. To date, disciplinary research has dominated, there still are too few interdisciplinary contributions about health and residential environments, and transdisciplinary contributions are even more rare. Transdisciplinary research and practice require a common conceptual framework and analytical methods based on shared terminology, mental images and common goals. Once these have been formulated, then the next requirement is to develop a research agenda based conceptually and pragmatically on diverse sources of data and information that can be organised in ways to help understand, interpret and deal with problems. There are several ways of promoting transdisciplinary approaches. The problem-solving approach, for example, can be used. It is typically small-scale, locality specific, and it is therefore appropriate for the study of health and housing in precise localities. This kind of approach can identify and explain what factors are pertinent in order to analyse and deal with problems that are frequently complex. Examples of this kind of approach are included later in this Symposium.