The last 200 years have altered our life expectations beyond all recognition. But the resulting population explosion threatens what we have gained in scientific progress. In understandable lay terms, Dr. John Cairnsrecently retired from the Harvard School of Public Healthexplains what is known about cancer, molecular biology, and virology, and how new breakthroughs in these areas are likely to affect future generations. Illustrated. Copyright (C) Muze Inc. 2005. For personal use only. All rights reserved.