The book "Subspeciation of the Meadow Mouse, Microtus pennsylvanicus, in Wyoming, Colorado and Adjacent Areas" by the well-known author Sidney Anderson is an important study of the diversity of mouse species in the natural conditions of these regions of North America. The book examines in detail the features of the morphology, behavior and ecology of the meadow mouse from different populations and identifies the factors leading to subspeciation. The author highlights the results of his research conducted along the geographical distribution of this mouse species, conducts a comparative analysis between subspecies and reconstructs their evolutionary history. The book reflects important scientific findings that are relevant to ecologists, zoologists, and evolutionists. "Subspeciation of the Meadow Mouse, Microtus pennsylvanicus, in Wyoming, Colorado, and Adjacent Areas" is essential reading for anyone interested in the biology and study of species in the wild.