It is a detailed history of the understanding of how the machinery of life and reproduction works, from the ideas of the ancient philosophers through to Darwin, Mendal, Watson & Crick and on to the scary world of re-programming the human genome. The genetic system of DNA to RNA to Protein to Organism is so simple in principle yet so complex in practice. It is fascinating to read how progress in unpicking this story was made by slow and difficult steps with many blind alleys. You realise that from a genetic point of view everything is just variation, and the idea of "normal" is simply a human construct. The burning question is, how far are we a machine programmed by our chemistry? What choices do we really have? The author envisages an experiment in which 100,000 babies from across the world have their genetic codes sequenced and stored and then tracked through their lives to see how the 100,000 selves develop in terms of all their physical, mental, emotional and cultural attibutes. Once the results of such an experiment were know how much of the "me" in me would be left? One thing genetic research has already made clear in the "nature v nurture" debate, is that "nature" is by far the most important factor in making us who we are.