The theme of this Symposium -Transdisciplinarity in people-environment relations suggests that collaboration between disciplines should be looked at from another perspective than the ones usually coined by the expression interdisciplinarity, multidisciplinarity or pluridisciplinarity. Transdisciplinarity in contrast suggests the mutual transformation of the involved disciplines and the exclusive character of the knowledge generated. This paper attempts to illustrate this theoretical mutation process in the context of a research and intervention programme addressing the renewal and intensification of postwar suburbs of Quebec.