This report looks at how transdisciplinary research, which combines knowledge from different scientific disciplines with that of public and private sector stakeholders and citizens, can be used to address complex societal challenges. This includes developing effective responses in acute crises, such as the COVID-19 pandemic, as well as longer-term solutions for sustainability development. In a series of 28 case studies, each of which is briefly summarised in the report, it identifies the key obstacles to effectively implementing transdisciplinary research. Many of these are embedded in the way that research systems are structured and managed and they are amenable to policy intervention. Examples of how various actors, including funding agencies and universities are adapting to better accommodate the requirements of transdisciplinary research are included in the report and related policy actions are ascribed for these actors.