The book comprehensively describes a unique phenomenon of nature - geysers and the conditions for their appearance in the Valley of Geysers in Kamchatka based on the results of more than 25 years of detailed research by the authors. Physical and geographical conditions, thermal fields and sources of the region, geology and hydrogeology of the Geyser Valley, thermal fields and hot springs in the surrounding landscape, the mechanism and mode of action of geysers, the composition of thermal waters and geyserites are briefly described.