**Can we change the minds of science deniers? Encounters with flat earthers, anti-vaxxers, coronavirus truthers, and others.** “Climate change is a hoax—and so is coronavirus.” “Vaccines are bad for you.” These days, many of our fellow citizens reject scientific expertise and prefer ideology to facts. They are not merely uninformed—they are misinformed. They cite cherry-picked evidence, rely on fake experts, and believe conspiracy theories. How can we convince such people otherwise? How can we get them to change their minds and accept the facts when they don’t believe in facts? In this book, Lee McIntyre shows that anyone can fight back against science deniers, and argues that it’s important to do so. Science denial can kill. Drawing on his own experience—including a visit to a Flat Earth convention—as well as academic research, McIntyre outlines the common themes of science denialism, present in misinformation campaigns ranging from tobacco companies’ denial in the 1950s that smoking causes lung cancer to today’s anti-vaxxers. He describes attempts to use his persuasive powers as a philosopher to convert Flat Earthers; surprising discussions with coal miners; and conversations with a scientist friend about genetically modified organisms in food. McIntyre offers tools and techniques for communicating the truth and values of science, emphasizing that the most important way to reach science deniers is to talk to them calmly and respectfully—to put ourselves out there, to meet them face to face.