The fifth book of the six-volume book of selected works by academician V.M. Kotlyakov summarizes the latest information about "wide" glaciology, covering all types of snow and ice. The book is based on the author's research in Novaya Zemlya, the Caucasus, the Pamirs, Antarctica, his travels in the glacial regions of the world: in Scandinavia and the Alps, Alaska and Patagonia, in the Arctic and China. It introduces the peculiarities of snow and ice phenomena on Earth, the history of their development, and the significance in people's lives. The book is based on a course of lectures delivered by the author at a number of universities. It can serve as a textbook, a textbook on modern glaciological problems.