Michael R W Brown is an internationally renowned microbiologist, who has devoted his scientific career to the study of microbial survival. In this book, he applies lessons learnt at cellular level to human life. He sees profound and urgent questions arising from the successful adaptation from a pre-modern, arboreal environment with our pre-human, ancestral brains. We still have instincts that enabled survival of our predecessors living in small groups in trees. These instincts can and do impel us towards behaviour inappropriate for human survival. Can modern humans survive the modern world?