The loss of water from lakes, rivers, oceans, vegetation, and the earth, as well as man-made structures such as reservoirs and irrigation conduits, is a major concern of hydrologists and irrigation specialists. This loss, compounded by the lack of usable water in some areas, indicates a need for field and laboratory research that will contribute to the understanding of the processes and parameters that comprise and contribute to evaporation. This book emphasizes the process of the air-water interface and discusses such important topics as evaporation and condensation coefficients of water, heat and mass transfer, surface temperature, interfacial tension, convection, diffusion, thermal gradients, wind-generated waves, and the roles that these processes play in evaporation. The book also discusses subjects such as methods for suppressing evaporation using films, water vapor distribution, wind tunnel investigations, evaporation from water drops, preparation of pure water, molecular diffusion, the eddy-correlation method, and evaporation estimation methods. The book will be of considerable value to hydrologists, irrigation specialists, meteorologists, civil engineers, chemical engineers, hydraulic engineers, water resources specialists, water conservation specialists, geophysicists, environmental engineers, and anyone interested in understanding the evaporation of water and its consequences.