The DSM-IV, like its predecessors, will be a major influence on American psychiatry. As a consequence, continuing analysis of its assumptions is essential. Review of the manuals as well as conceptually-oriented literature on DSM-III, DSM-III-R, and DSM-IV reveals that the authors of these classifications have paid little attention to the explicit and implicit value commitments made by the classifications. The response to DSM criticisms and controversy has often been to incorporate more scientific diversity into the classification, instead of careful inquiry and assessment of the principal values that drive the nosologic process. Implications for psychiatric science and future DSM classifications are discussed.