This paper critically reviews the three main approaches to land degradation and conservation - the classic, populist and neo-liberal. The implications of these paradigm shifts are examined in terms of research needs. Next, the paper discusses the role of science and technology, and the origins and substance of differences in the perception, evaluation and diagnosis of degradation. Focus is then shifted to analyzing how farmers and pastoralists make decisions about resource use and management, and a research approach is suggested for analyzing decision-making. Two case studies illustrate the approach.
