There is something special about cancer compared to other diseases. It is a horrific disease that has defied attempts to find a reliable cure. Life spans after diagnosis have increased, but the mortality rate has remained about the same even after 40 years of extensive research. Cancer provides a major scientific challenge. Tumors evolve and spread in response to internal and external factors that involve feed-back mechanisms and non-linear behavior. In recent years, physicists have become involved in studying cancer, with the ultimate aim of finding a cure. Physicists approach a problem with...