Our bodies and body processes evolved to allow our ancestors the best chance of survival as hunter-gatherers in the Savannah. Our brains, on the other hand, have evolved intelligence, imagination, and foresight, allowing us to leave all other creatures behind, and develop complex societies, cultures, and lifestyles, far removed from those of our ancestors. The development of a modern human in utero still reflects our past, and we have created a modern, artificial world that is out of tune with our evolved bodies. Could it be that this mismatch has led to the current deadly explosion in 'lifestyle' diseases such as diabetes and obesity, and will it lead to increasingly frequent epidemics? We appear unable to evolve out of this problem, and unwilling to return to a different way of life, so how can we understand and address this increasingly crucial challenge? Gluckman and Hanson set out the case, examining issues that are at times controversial and speculative. Utilizing the latest research in epigenetics (that genes may be environmentally modified), they propose that intervention in early human development, alongside a better focus on the health of potential mothers, can make future generations better suited to the modern world.