Cancer has become the scourge of the twentieth century. It was always part of the human condition, but until recently it was not a common cause of death because most people died from the infectious diseases. Now that so many of us will live long enough to develop cancer, we need to learn as much about it as we can. This requires some understanding of molecular biology. John Cairns has made significant contributions to cancer research, molecular biology, and virology. He believes that it is possible to explain what is known about cancer and about molecular biology in terms that are easily understood by people with little or no scientific training. In this fascinating book, he explores the revolution in public health, the origins and principles of molecular biology, and our emerging understanding of the causes of cancer. Finally, he discusses how these developments are likely to affect future generations. As Cairns points out, the last two hundred years have altered our life expectations beyond all recognition. Even in the less developed nations of the world, people are starting to believe that everyone ought to be able to live into old age and be protected from the major causes of premature death. This change in our expectations is one of the major benefits of technology and the biological sciences. But the resulting explosion in the human population ultimately threatens everything we have gained by scientific progress.