Nonhuman primates have played critical roles in biomedical research, and they are among the few animals whose use in research continues to increase. The scienti?c value of nonhuman primates derives from their close phylogenetic proximity to man and their consequent anatomic, physiologic, and genetic similarities to man. Only nonhuman primates can provide adequate models for many complex physiological and disease processes of humans. The baboon is a relative newcomer to the repertoire of nonhuman primates used in biomedical research. However, in less than 50 years since its ?rst use in the U....