This book was originally published in paperback in 1991, during a time of growing global concern over the loss of gene resources in crop plants. The future was seen as being dependent on their immediate conservation and effective use by plant breeders. The text is aimed at providing a comprehensive introduction to the form and availability of crop diversity, as well as how this diversity may be gathered, conserved and ultimately combined with new cultivars. Techniques are defined within the fields of data management, tissue culture and genetic engineering, and the overall concept of plant genetic resources is discussed within a political context. A comprehensive bibliography is included.