The economic costs of frosts in agriculture and horticulture in many parts of the world can be very significant. Reports in the media include accounts on how frosts have devastated coffee crops in Brazil or in Papua New Guinea, and how frosts have seriously damaged the Florida citrus industry. Frost may cause losses in current harvests or a decline in future yields through more permanent damage to trees and bushes. Damaging frosts may occur as infrequent, short-term events with sub-zero temperatures or with unusually severe winter temperatures which extend over long periods. In this book we have aimed at providing a comprehensive review of recent advances in the area of frost research. The stimulus for writing this book has come from the recognition that there is a shortage of recent texts which deal exclusively with the bioclimatology of frost. Bioclimatology deals with the relations between climate and life and the present text is particularly concerned with the effects of low temperatures on plants. Our purpose has been to assist researchers, engineers, extension officers and students in understanding the physical aspects of frost occurrence and frost distribution as well as the biological and phenological aspects of frost damage and to provide an overview of direct and indirect methods of frost pro­ tection and prevention.