<P>Crop plant varieties developed by local farmers, commonly referred to as ‘farmers' varieties’, are a problematic subject, because there are no fixed taxonomic or legal definitions of them. As a result, policies to increase the share of benefits farmers receive from the use of such varieties struggle to have an effect. </P><P>This volume aims to clarify these issues, beginning with the biological and social complexities of defining what ‘farmers’ varieties’ are, and how they differ from one another and from generic varieties. Alongside this, the book charts the evolution of the concept of ‘Farmer’s rights’, from the dawn of 'genetic resources' as a subject worthy of international attention, to the first legal recognition of the concept in an international treaty in 2001, through to current efforts to develop national level policies and laws. Finally, the book examines outstanding policy-making challenges linked to the absence of fixed taxonomic or legal definitions of farmers' varieties. </P><P>Various solutions are considered, based on revised or new definitions of farmers' varieties that reflect the biological and cultural realities in which they are produced, and the relative costs and benefits of attempting to implement each of the policies discussed. The book takes in to account the manner in which public debate concerning policy options has evolved over the course of the last 20 years, and how that evolution compares with actual experiences of implementing those policies. This treatment includes case studies of actual situations 'in the field' where farmers, researchers and policy advocates have been confronted with the issues raised in this book. </P>