We think we know bullshit when we hear it, but do we? Two science professors give us the tools to dismantle misinformation and think clearly in a world of fake news and bad data Politicians are unconstrained by facts. Science is conducted by press release. Start-up culture elevates hype to high art. The world is awash in bullshit, and we're drowning in it. Based on a popular course at the University of Washington, this book gives us the tools to see through the obfuscations, deliberate and careless, that dominate every realm of our lives. In this lively, provocative guide, biologist Carl Bergstrom and data scientist Jevin West show that calling out nonsense is crucial to a properly functioning social group, whether it be a circle of friends, a community of researchers, or the citizens of a nation. Through six rules of thumb, they help us to recognize when numbers are being manipulated, to cut through the crap wherever we encounter it - even within ourselves - and learn how to give the real facts to a crystal-loving friend or climate change denier uncle. Calling Bullshit is an indispensable handbook to the art of scepticism.