Felix Oppenheim has devoted his scholarly life to conceptual analysis in the service of ethical and metaethical understanding. He has illuminated some of the most important political-ethical concepts, including freedom, equality and power. And though he is sympathetic to the project of achieving for the study of politics a conceptual clarity comparable to that often found in natural science, he is admirably tentative in the face of recalcitrant complexity. He has even gone so far as to end his magisterial essay, "The Language of Political Inquiry", with four sets of "unresolved issues' that leave his readers with a sense of Oppenheim's own inclinations but also provide some assistance in taking issue with him.1 This open-mindedness, despite strongly held views, makes reading him especially valuable.