The book "Speciation and Evolution of Pygmy Mice of the Genus Baiomys" by Robert L. Packard is an important scientific study devoted to the study of the evolutionary development and speciation of pygmy mice. The author investigates in detail the mechanisms that lead to the formation of new species in the genus Baiomys, considering ecological, genetic and behavioral factors that influence this process. Due to the high level of detail and validity of the conclusions, the book is an important addition to modern research in evolutionary biology and genetics. The publication is recommended to everyone who is interested in the study of evolutionary processes in nature.