There is currently a great deal of published research and information on the ways in which captive environments of non-human primates could be improved. This material is widely dispersed throughout the scientific literature so it is particularly helpful that the United States Department of Agriculture has published a valuable source of information on this subject. The booklet is comprehensive and not only provides an invaluable classified bibliography but also has an author index, a list of organizations which can provide information on non-human primates, how they can be contacted and details about their activities. There is a useful list of journals which publish information on primates - although unfortunately Animal Welfare is omitted despite a number of its papers being included in the reference list.