Agriculture lies at the heart of Africa's development. It underpins food and nutrition security, generates export earnings, provides raw materials for local industries, and serves as a foundation for economic wellbeing and socio-political stability. Yet despite its vast agricultural potential and abundant natural resources, Africa continues to face a profound agricultural challenge. Rapid population growth-projected to exceed 2.5 billion people by 2050-demands significant increases in agricultural productivity, greater export competitiveness, expanded import substitution, and stronger support for agriculture-based industries. This timely volume examines two critical pillars of agricultural transformation in Africa: diversification and value addition. Drawing on evidence from across the continent, it provides an in-depth assessment of the current state of agricultural production and trade, highlighting persistent structural weaknesses. In 2023, Africa spent more than US$117 billion on agricultural imports while earning only US$73 billion from exports. Most imports were food products, while the majority of agricultural exports left the continent with little or no value addition. Intra-African agricultural trade also remains disproportionately low compared with other regions of the world, such as Europe or Asia. The book traces the history of diversification efforts launched by many African governments from the late 1960s onwards, when countries sought to reduce dependence on a narrow range of commodities such as cocoa and coffee. It evaluates the outcomes of crop introduction and promotion initiatives, explores their implications for biodiversity and market sustainability, and identifies lessons that can inform future policy. Particular attention is given to opportunities for developing both new and adapted crops capable of supporting a more resilient and diversified agricultural sector. By providing a comprehensive analysis of past experiences and future possibilities, this book offers valuable guidance for policymakers, development practitioners, agricultural research organizations, scholars, and graduate students seeking to advance Africa's agricultural transformation agenda.