People in drylands are vulnerable to the effects of drought and climate change, particu - larly in the drylands of developing countries where high poverty levels limit their ability to cope. This is the case in the drylands of Eastern Africa, where the combination of en - demic poverty and frequent drought have led to a situation where relief has overtaken development as the major area of investment. In recent years it has been realized that there is a need for development, which rebuilds the drought resilience of the region’s dryland economies. Trees can enhance resilience of livelihoods in drylands, but their exact contribution has been poorly explored. Approach and structure This book is the result of a consultative process, which brought together experts from Eastern Africa and beyond to synthesize and compile existing information on the role of trees in building resilience in the region’s drylands. The group consisted of a mixture of experts with backgrounds in research, academia, government, farmers and devel - opment practitioners, and the book reflects the knowledge and perspectives of these various groups. The book begins by describing the rationale behind the initiative followed by a clarifica - tion on the background and approach taken. Chapter three then describes the Eastern African region and argues why there is a need to build resilience in the livelihoods of communities living in drylands. Chapter four builds on this by introducing an ecosystem services perspective as the conceptual framework to explore the resilience offered by trees. Chapter five reviews the ecology, distribution and use of trees throughout the Eastern African region. Chapter six uses an ecosystem service perspective to review the various benefits that people derive from dryland trees. Chapter seven draws on experiences gained in development practices and presents and reviews 11 case studies of natural resource management. Chapter eight presents reflections of the write-shop participants on how best practice in resilience-building could be scaled up. A review of knowledge and information gaps regarding the contribution of trees in building resil - ience is presented in chapter nine, which is followed by a plan for possible follow-up action in chapter ten.