Epistemology of motivation harnesses the art of motivation. It analyzed and explained motivation and what motivate people. Targeting employee motivation epistemology of motivation reviewed the motivational theories and discussed their strengths and weaknesses. The theories analyzed include: the Maslow's needs hierarchy Goal setting theory theories and X Y and Z the Management by Objective and the newly Humanistic Influence and Affluence factors. Various scholarly reports published within the past fifteen years were analyzed and referenced.