Conspiracy theories, rumors, and fake news are what we encounter every day. Lies are spread by our friends, our relatives, and even by ourselves. Neither education nor the ability to reason logically protects us from it—only intensifies the effect. Science journalist Borislav Kozlovsky set out to figure out what genes, the brain, and big data have to say about all of this. Where in our DNA is susceptibility to political propaganda “encoded”? How do the “Facebook algorithms” and matchmaking-site experiments affect us? And why do rational arguments accomplish nothing against the misconceptions we once believed with all our hearts? The author doesn’t promise that after reading this book you’ll stop fooling yourself. But watching how others do it will be many times more interesting.