The Critical Assessment of the classical sociology of knowledge, especially of its Mannheimian version, which has been in evidence for nearly sixty years even among otherwise radically different theoretical traditions in the social sciences and philosophy, is at once surprising and significant. If we take the widespread cognitive disagreement among sociological traditions (see Merton 1978) as an initial criterion, then it might be expected that assessments of the basic claims advanced by the sociology of knowledge would vary greatly.