In this article, I discuss our current understanding of the structural features of the microtubule-dependent motor kinesin and its relatives, which are needed for force generation. It has become clear that the motor domain itself is likely to be only about 340 amino acids, and that direction of movement is also controlled within this region. There is reason, however, to be suspicious that elements in the tail that are located immediately adjacent to the motor region influence, or in some way contribute to, normal motor activity. Finally, I describe recent work designed to identify the regions involved in the kinesin-microtubule interaction.