Because of the toxic effects of tobacco smoke, addiction to tobacco smoking is one of the worlds most critical public health problems. Worldwide, tobacco smoking causes over 5 million deaths each year (more than the current population of Los Angeles California), and it is projected that by 2025 smoking will cause over 10 million deaths each year (more than the current population of New York City). In the USA, smoking is the largest single preventable cause of death; it causes one in five deaths, and 435, 000 people will die prematurely from smoking-related diseases each year. It causes more deaths than the combined sum of all the deaths caused by HIV, illegal drugs and alcohol use, motor vehicle accidents, and murders taken together. World wide half of the 1.2 billion smokers will die of tobacco related illnesses, and it is estimated that in the USA smoking causes 30% of all cancers and 80–90% of all lung cancer deaths. Tobacco use is estimated to cause an economic burden of $197 billion per year in the USA.