This book addresses the biodiversity dimensions of the challenge of eradicating hunger and malnutrition and makes the case for re-examining food systems and diets. The book is also intended to be used as a tool and a guide to promote the use of biodiversity within food production systems, and to demonstrate that by providing local solutions for diversifying diets, nutritional status can be improved, effectively and sustainably. The first half of the book outlines some of the challenges, and identifies potential solutions and opportunities to conserve, measure, and utilize biodiversity for improved diets and nutrition security. The second half provides 12 case studies on the links between agricultural biodiversity and diets and nutrition. Sustainable diets are defined as those which are respectful of biodiversity and ecosystems; culturally acceptable, accessible, economically fair and affordable; nutritionally adequate, safe and healthy; while optimizing natural and human resources. The book is part of a larger series titled Issues in Agricultural Biodiversity.