Wherever our origins ultimately lie, there is no rational doubt that we Homo sapiens are proximally the product of an eventful evolutionary past. Our ancient history is richly documented by a fossil record that is remarkably abundant for one single family of primates, and that is certainly a lot better than most paleoanthropologists are prepared to concede as they write funding proposals for more fossil exploration. Saying this is not, of course, to deny the huge value of such exploration. Fossil records are by their nature incomplete; and in a science in which every answer leads to compelling new questions, it is important to flesh them out as much as possible.
Still, what we already know allows us to construct a fairly convincing outline sketch of human prehistory, and of the natural context in which it played out.