Over the last 20 years, the geographic spread of ATREE's work has expanded from the Western Ghats and Eastern Himalayas, to the almost entire country, and from forests to grasslands, wetlands, and peri-urban landscapes. Alongside. the focus of our work has expanded from studying biodiversity to analysing the biophysical and socio-economic drivers of ecosystem change, and their implications for conservation and sustainable development. Yet the core of what we do has remained the questioning and interrogating the prevailing paradigms, and the productions of rigorous inter-disciplinary knowledge that can inform civil society and policy makers. the present volume is an effort to share this 20-year history of ATREE.