We find risk everywhere–from genetically modified crops, medical malpractice, and stem-cell therapy to heartbreak, online predators, identity theft, inflation, and robbery. They arise from our own acts and they are imposed on us. In this Very Short Introduction, Baruch Fischhoff and John Kadvany draw on both the sciences and humanities to illuminate both the similarities and differences of various kinds of risk. They examine the science and practice of creating measures of risk and look at how scientists apply probability by combining historical records, scientific theories, and expert judgment. More importantly, they show what science has learned about how people deal with risks, applying these lessons to diverse everyday examples.