This Open Access book deals with the pressing question of how to achieve transformational
change that reconciles development with environmental sustainability. It particularly focuses
on the role of evaluation in finding sustainable solutions. Environment and development are
closely interlinked as are human health and ecosystem health. The pandemic that began in 2020
demonstrated in no uncertain terms how destruction of habitats has allowed hitherto unknown
pathogens spill over to humans wreaking havoc on people's lives and livelihoods. We are already
seeing the impacts of global climate change in terms of heatwaves forest fires and increased
storms. The Sustainable Development Goals (SDGs) explicitly recognize the equal importance of
the social economic and environmental dimensions of development. In these turbulent times
when humankind faces multiple complex challenges it is essential to know that our responses are
effective and that they make a positive difference. Evaluation can provide invaluable lessons
to how we design policies strategies and programs and how we allocate limited resources
between competing priorities. This book brings together key thinkers and practitioners from the
public and private sectors from major multilateral organizations and from bilateral donor
agencies to present the latest knowledge and experience on how to evaluate interventions in
the nexus of environment and development. The book does not promote any particular approach or
methodology but rather emphasizes the need for mixed methods to address the question at hand
in the best and most suitable manner. It covers cases from a variety of fields from climate
change mitigation and adaptation energy efficiency and renewable energy natural resources
management biodiversity conservation and more. This book is not a conference proceedings
although it has its roots in the Third International Conference on Evaluating Environment and
Development organized by the GEF Independent Evaluation Office in October 2019. The conference
brought together a larger number of established and upcoming evaluators researchers and
evaluation users from the Global North and South representing a wide variety of organizations
to discuss the frontiers of environment and development evaluation. Following the conference
the editors identified and contacted the participants who made key contributions at the
conference and asked them to develop their ideas and papers into book chapters according to a
coherent plan.