The paper attempts to identify the extent to which modes of knowledge can be associated with different patterns of and assumptions about power. It discusses the meanings and scope of power itself, i.e. both within and beyond epistemic communities, as against "social robustness" implying more democratic or inclusive forms of evaluation. It analyses the extent to which knowledge has shifted from an internalist perspective relying on the prestige of epistemic communities towards socially relevant assumptions resting within social contexts. It discusses the factors affecting types of power patterns, such as: the nature of sponsors' objectives and the uses to which they might put knowledge; epistemic characteristics; the nature of the resource required, and the stage of finalisation reached. It sketches the range of models of sponsorship to which knowledge is subjected--from that of the free standing and autonomous individual through different patterns of sponsorship to the directly managed. It attempts to link these classifications to a range of empirical examples, including the power of knowledge in government and in crossing the boundaries between universities and industry. In discussing the reciprocal relationships between power and knowledge, it accepts that power affects the identification, use and transmission of knowledge. It is concerned, however, to question over determined perspectives of the relationships between knowledge and power whose mutual impacts may be strong but not easily predicted or defined.