Abstract
PurposeTransdisciplinarity was the core subject of a special issue of Futures in 2004 including numerous cases of interdisciplinary and transdisciplinary architectural and urban research and professional practice in several countries. This paper takes stock of achievements during the last 20 years before presenting challenges about bridging persistent gaps between theory, research and practice.Design/methodology/approachThe special issue of Futures is a benchmark for numerous publications about transdisciplinarity in and beyond the multidisciplinary and intersectoral field of built environments. This paper presents a narrative literature review of publications about transdisciplinarity in architecture, urban design and planning since the 1970s.FindingsTransdisciplinarity is still being debated, is often contested, and is not mainstream in research or practice. Like design practice, transdisciplinary inquiry is a creative process involving border work by participants in collaborative projects. Transdisciplinary inquiry is broader in scope and purpose than public participation, participatory action research and team science.Originality/valueThis paper discusses challenges that should be addressed by those in the field of built environments who endorse transdisciplinarity. Based on a half century of contributions about design theory and methods, the paper differentiates inquiry from research as fundamental to transdisciplinary projects.