The Science of Algorithms: 203

An algorithm is a set of instructions designed to accomplish a task, solve a problem, make a prediction, or recommend something you absolutely did not know you needed until an advertisement followed you into the bathroom. Algorithms sort information, calculate routes, approve loans, detect fraud, recommend movies, schedule workers, match romantic partners, control traffic lights, guide spacecraft, predict storms, and decide whether the photograph you posted contains a smiling family or seven suspiciously upright houseplants. They operate everywhere, usually without introducing themselves.The basic idea is not new. Long before computers, people followed procedures for dividing numbers, navigating oceans, organizing libraries, baking bread, collecting taxes, and determining which royal cousin should inherit a kingdom without starting a twenty-year war. A recipe is a kind of algorithm. So is a checklist, a dance routine, a legal procedure, and the method your grandfather used to start a lawn mower by pulling the cord three times, whispering a threat, adjusting the choke, and blaming modern gasoline. Algorithms are simply organized steps, although some are considerably better organized than others.