This study elucidates and appraises a conception of praxis developed by the Yugoslav Marxist Mihailo Markovi . This notion is first distinguished from everyday and alternative theoretical uses of 'practice', 'practical', and 'praxis' . Markovic's view is then characterized as a normative, pluralistic theory of both human being and doing. Praxis , for Markovi , is activity which realizes one's best potentialities: (i) the humanly generic dispositions of intentionality, self-determination, creativity, sociality, and rationality, and (ii) one's relatively distinctive abilities and (...) bents compatible with (i). Following a critical analysis of Markovic's attempts to justify praxis as norm, two substantive criticisms are advanced. The theory needs (i) priority rules for the relative weighting of praxis components when they cannot all be (fully) realized in an action, and (ii) a specification of the genus praxis so as to recognize important differences among optimal activities which shape things, construct theories, rear children, and share with mature persons. (shrink)