This monograph deals with the subfamily of voles (Microtinae) -- the group of rodents which are of great practical importance as pests of agricultural crops as well as carriers and reservoirs of pathogens of several infectious diseases of animals and man. The introductory part describes the body structure and its adaptive peculiarities, geographical distribution, history of study of the group and its phylogeny. The taxonomic part presents characteristics of more than 130 extant as well as extinct species combined into 42 genera and 8 tribes. The monograph concludes with a special section (by I. Ya. Polyakov) containing detailed biological characteristics of individual groups of voles including the data on the structural peculiarities and population dynamics, economic importance and control measures under different natural conditions.