This paper discusses the experiences of the author as an expert witness directly involved in litigation on desegregation. Using four court cases, it points out differences between social science and the law that restrict the use of social science testimony in public school desegregation cases. Four interrelated elements that contribute to this tension, discussed in depth, are (1) contrasting conceptual definitions, (2) differences in preferred scope, (3) different frameworks, and (4) conflicting operational environments. Finally, suggestions are offered by which the inherent tensions between the two disciplines can help to sharpen the perspective of each. (Author/LD)