Merchants of Doubt is a 2010 book by the American science historians Naomi Oreskes and Erik M. Conway. It identifies parallels between the climate change debate and earlier controversies over tobacco smoking, acid rain 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 say 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.
Most reviewers received it favourably. One reviewer said that Merchants of Doubt is exhaustively researched and documented, and may be one of the most important books of 2010. Another reviewer saw the book as his choice for best science book of the year. Philip Kitcher in Science says Merchants of Doubt is a "fascinating and important study". The book was made into a film, Merchants of Doubt, directed by Robert Kenner, released in 2014.