This book contains several well researched topics associated with various aspects and properties of evapotranspiration. These fields are the leading technologies that measure the extremely spatial ET from the planet's surface. The analyses explain technicalities of ET simulation from incompletely vegetated surfaces and stomatal conductance behavior of natural and agricultural ecosystems. Evaluation strategies that use weather based ways such as soil water balance, temperature-radiation based methods and many others have been explained. Suggested guiding principles for applying operational satellite-based energy balance models and overcoming common challenges have also been included.