The aim of this manual is to provide pracitical guidance to researchers committed to promoting the better use of tropical feed resources in sustainable livestock systems. The emphasis is on appropriate technologies for small farmers in developing countries. The first part deals with the principles of non-ruminant and runinant nutrition, the identification of feed resources and their utilization. Various practices are described for improving the use of natural renewable resources. Methods that should assist the research worker in conducting useful and cost-effective research are given in detail.