Evapotranspiration is the total water loss by plants to atmosphere in the form of transpiration and evaporation. Specialists in the field of evapotranspiration with extensive expertise have collaborated to bring forth this text which elaborates the latest developments in physics of the processes of evaporation and evapotranspiration. With path-breaking and up-to-date research on methods and templates used globally, it presents the role of modern technology and instrumentation. Those who read or refer to this text will benefit vastly from the in-depth analysis and the diverse backgrounds and setups, where the models, utilization and methods have been put to test. Numerous factors affect and influence the perceived and actual demand of water aby the atmosphere. This book presents not only the information to improve the procedures for estimating evapotranspiration, but also provides students and scientists with pathways to interpret, manage and evaluate the observed data.