Although denialists, according to Specter, come from both ends of the political spectrum, they have one important trait in common: their willingness to replace the rigorous and open-minded skepticism of science with the inflexible certainty of ideological commitment. Specter analyzes the consequences of this inflexibility and draws some startling and uncomfortable conclusions for the health of both individuals and society. For example, though every reputable scientific study demonstrates the safety of major childhood vaccines, opponents of childhood immunization are winning the publicity war; childhood immunizations are tumbling and preventable diseases are increasing, often leading to unnecessary deaths. Specter, a New Yorker science and public health writer, does an equally credible job of demolishing the health claims made by those promoting organic produce and all forms of alternative medicine. Specter is both provocative and thoughtful in his defense of science and rationality—though he certainly does not believe that scientists are infallible. His writing is engaging and his sources are credible, making this a significant addition to public discourse on the importance of discriminating between credible science and snake oil.