Do you touch wood for luck, or avoid hotel rooms on floor thirteen? Would you cross the path of a black cat, or step under a ladder? Is breaking a mirror just an expensive waste of glass, or something rather more sinister? Despite the dominance of science in today's world, superstitious beliefs - both traditional and new - remain surprisingly popular. A recent survey of adults in the United States found that 33 percent believed that finding a penny was good luck, and 23 percent believed that the number seven was lucky. Where did these superstitions come from, and why do they persist today? This Very Short Introduction explores the nature and surprising history of superstition from antiquity to the present. For two millennia, superstition was a label derisively applied to foreign religions and unacceptable religious practices, and its primary purpose was used to separate groups and assert religious and social authority. After the Enlightenment, the superstition label was still used to define groups, but the new dividing line was between reason and unreason. Today, despite our apparent sophistication and technological advances, superstitious belief and behaviour remain widespread, and highly educated people are not immune. Stuart Vyse takes an exciting look at the varieties of popular superstitious beliefs today and the psychological reasons behind their continued existence, as well as the likely future course of superstition in our increasingly connected world.