This guide recommends 350 old-fashioned varieties of vegetables that should make gardening more satisfying, and cooking and eating more enjoyable. A total of only 30 plant species account for 95 per cent of the crops grown for human consumption. Modern varieties have been developed for their high yields, bright colours, regular shape and size and their convenience to pack. But organic growers argue for diversity. The authors argues that a lack of diversity can result in genetic wipe-out, such as in the case of the Irish potato famine of the 19th century, when all the potatoes came from a similar genetic base and were vulnerable to the same spread of disease. Part One of the book discusses the central issues, including The Importance of Diversity , Pressures for Conformity and Saving the Seed . Part Two lists old varieties available today, with the history and origins of vegetables. The book demonstrates how, by focusing on variety rather than the uniformity of modern vegetables, gardeners can maintain genetic diversity, enhance resistance to pests, diseases and climatic change, and ensure the security of food supplies for a sustainable future. Sue Stickland is the author of G is for EcoGarden , Organic Gardening and The Small Ecological Garden .