Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming is a 2010 non-fiction book by American historians of science Naomi Oreskes and Erik M. Conway. It identifies parallels between the global warming controversy and earlier controversies over tobacco smoking, acid rain, DDT, and the hole in the ozone layer. Oreskes and Conway write that in each case "keeping the controversy alive" by spreading doubt and confusion after a scientific consensus had been reached was the basic strategy of those opposing action. In particular, they show that Fred Seitz, Fred Singer, and a few other contrarian scientists joined forces with conservative think tanks and private corporations to challenge the scientific consensus on many contemporary issues.

Naomi Oreskes is an American historian of science. She became Professor of the History of Science and Affiliated Professor of Earth and Planetary Sciences at Harvard University in 2013, after 15 years as Professor of History and Science Studies at the University of California, San Diego.