Histories are subject to different interpretations. We would expect biological history to conform to this variety of understandings. But the strange thing is that the very existence of biological history is denied in some quarters. This field of science has acquired a ‘more than scientific’ aura to it. People argue about it as if it were an ideology. Vast resources, including a lot of goodwill, have been expended in the debate. To have achieved this notoriety, we must conclude that biological history (or evolutionary biology) is widely misunderstood. But the evidence for it is there; and a vast volume of fresh genetic data has been added recently. Such data are compelling.

This is a history book, and for two reasons. It attempts to describe, in a very limited and situated sense, a spectacular period in the history of science. Its timeframe covers, with somewhat fuzzy edges, the first decade of the twenty-first century. This is the period during which the human genome sequencing project has been elaborated to ever increasing degrees of detail, and during which myriad fascinating insights into the biological basis of our humanness have been revealed.

Secondly, it describes the evolutionary history of our species, as inscribed in great detail in our genomes. The DNA that we carry around as part of our bodies is an extraordinary library of genetic information. But it is more than simply a blueprint for the human body plan; it also carries, inscribed in its base sequence, a record of its own formative history. Multiple other mammal and vertebrate genomes have also been sequenced over the last decade or so, and this means that we have access to their histories too.