A book focused solely on Andean Cloud Forests (ACF) has never been published. ACF are high biodiversity ecosystems in the Neotropics with a large proportion of endemic species, and are important for the hydrology of entire regions. They provide water for large parts of the Amazon basin, for example. Here I take advantage of my many years working in ACF in Ecuador, to edit this book that contains the following sections: (1) ACF over space and time, (2) Hydrology, (3) Light and the Carbon cycle, (4) Soil, litter, fungi and nutrient cycling, (5) Plants, (6) Animals, and (7) Human impacts and management. Under this premise, international experts contributed chapters that consist of reviews of what is known about their topic, of what research they have done, and of what needs to be done in the future. This work is suitable for graduate students, professors, scientists, and researcher-oriented managers.