In this chapter, I survey ideas of the concept of species, as they apply to the human evolutionary record. I discuss the question of the meaning of a genus, concluding that all species since the separation of the human line from that of the chimpanzee (and possibly including the chimpanzee lineage as well) should be placed in a single genus, for which the prior available name is Homo. How new species arise is a yet more controversial topic, and I list the variety of modes of speciation that have been proposed, with predictions as to what the results of some of these modes might look like, making suggestions as to how they might apply in palaeoanthropology.