How to avoid disease, how to breed successfully and how to live to a reasonable age, are questions that have perplexed mankind throughout history. This book explores our progress in understanding these challenges, and the risks and rewards of our attempts to find solutions. From the moment of conception, nutrition and exposure to microbes or alien chemicals have consequences that are etched into our cells and genomes. Such events have a crucial impact on development in utero and in childhood, and later, on the way we age, respond to infection, or the likelihood of developing chronic diseases, including cancer. The issues covered include the powerful influence of infectious disease on human society, the burden of our genetic legacy and the lottery of procreation. The author discusses how prospects for human life might continually improve as biomedicine addresses these problems and also debates the ethical checkpoints encountered.