This laboratory guidebook provides step-by-step procedures that will aid in the dissection and collection of major organs and tissues of the most common species of small animals used in biomedical research. Through extensive use of photographs and illustrations, the dissector is guided through a complete necropsy of each species for the purpose of collecting the organs and tissues routinely examined by pathologists. The techniques described will enable the technician to perform necropsies on almost any mammal in a precise and logical sequence, and to properly collect tissue in order to avoid diagnostic errors. Morphological differences among the various species are discussed.