The book synthesises the research, methods, and collaborative learning developed within the RE-DWELL Innovative Training Network, offering a comprehensive account of transdisciplinary approaches to affordable and sustainable housing. Structured in six progressive parts, it begins by mapping contemporary housing challenges across design, community participation, and policy domains, and then reconstructs the conceptual and pedagogical foundations of the project. It traces how the initial research framework—linking affordability, sustainability, and transdisciplinarity—was progressively articulated, operationalised, and critically consolidated through collaboratively and cross-disciplinary research and training practices. In doing so, it establishes affordable and sustainable housing as a transdisciplinary problem field and examines how transdisciplinary capacities were developed through the RE-DWELL learning and research environment, combining situated, practice-based learning with reflexive understanding of transdisciplinary inquiry. The core of the volume presents the fifteen early-stage researchers’ projects alongside shared knowledge resources—vocabulary, case library, and challenges repositories—developed within the network, illustrating how knowledge is collectively produced and integrated across disciplines and contexts. Subsequent sections examine how this transdisciplinary framework informs housing policy, resident engagement, and architectural education, while highlighting the central role of community co-creation in defining problems and solutions. The final part reflects on the integration of academic research with professional practice, particularly through secondments, emphasising the co-production of actionable knowledge. Overall, the book serves both as a synthesis of RE-DWELL’s evolving transdisciplinary research and learning framework and as a practical reference for advancing collaborative, socially inclusive, and sustainable housing strategies, with links throughout the text guiding readers to complementary online resources on the project website, extending its role as a shared knowledge resource.