Crop yields and vegetation productivity depend upon a very large degree on the interception of light by the leaf surface. Hence understanding of the generation of leaves, their persistence and eventual senescence, and their physiological processes are of paramount importance in the quest for increasing productivity. This book was first published in 1983 and was written by leading international experts. It provides an integrated, coherent account of these aspects. Although the chapters were written as components of an integrated advanced text, the principle contributors were able to present and discuss their concepts in conjunction with the Thirteenth International Botanical Symposium at the University of Sydney in August 1981. A valuable adjunct to the volume is a summary of this discussion. This is a useful study for all those interested in the history of research into physiology of plants, crop physiology, agronomy, horticulture and ecology.