In the current fad for omnibus histories of absolutely everything, designed to replace ancient metaphysics, perhaps, or answer some marketing brainwave, no one has succeeded in quite the way Christine Kenneally has. She approaches her task with a very specific enquiry: what is the interplay between genetics and human history? Searching for an answer, she uncovers worlds within worlds.

Kenneally brings the old nurture–nature debate into updated focus. Now that we have mapped the human genome and can test genetically for almost everything, what does this add to our understanding of ourselves – as individuals, as members of community, and as a species? Genetics has had an unpleasant intellectual history in racial supremacy theories, but in Kenneally’s hands it becomes something open-ended and expansive. Our common humanity trumps any attempt to divide us biologically, ethnically, politically, or by religion. In fact, DNA testing opens up many more questions than it closes down, and definitive answers about the genetic constitution of humanity – or anything else for that matter – are way off in the future.