In the 1950s, as evidence mounted that smoking caused cancer, tobacco companies launched an aggressive campaign in defense of their product. They tried to undermine studies that showed cigarettes were unhealthy; they did their own phony research that highlighted smokers without disease. It was one of the most dishonest PR offensives ever - and one you might think not likely to be repeated. Well according to our next guest, it has been repeated, again and again. Today the business of "product defense" is alive and well, fighting to muddy the data on the safety of everything from prescription drugs to plastic baby bottles. This business of "manufacturing uncertainty" is described in a new book by David Michaels called Doubt Is Their Product. He's an epidemiologist and former Assistant Secretary of Energy.