WALKER'S MAMMALS OF THE WORLD (2-VOLUME SET)

In 1930, the great mammalogist Ernest P. Walker (1891-1969), who was then assistant director of the National Zoo in Washington, D.C., set out to make a checklist of all the world's mammal species. Thirty-four years later, that simple catalog had grown into the huge first edition of Mammals of the World, a book dedicated to all mammals, "who contribute so much to the welfare and happiness of man, another mammal, but receive so little in return, except blame, abuse, and extermination."

Now in its sixth edition and compiled in two volumes, the even larger Mammals of the World contains thorough descriptions of every genus of the class Mammalia known to have lived in the last 5,000 years: 28 orders, 146 families, 1,192 genera, and 4,809 separate species. Volume 1 opens with the monotremes (including echidnas and the duck-billed platypus), which, write Walker and his successor Ronald Nowak, "resemble reptiles and differ from all other mammals in that they lay shell-covered eggs that are incubated and hatched outside of the body of the mother." The first volume then moves on to cover the insectivores, including an astonishing variety of bats, and closes with primates and carnivores. Volume 2 comprises the pinnipeds (seals and sea lions), moves through the cetacea (dolphins, porpoises, and whales) and artiodactyls (deer and their kin), and closes with a huge roster of rodents. It also contains an extensive bibliography numbering some 6,000 items, making the set of inestimable importance to students and professionals.