From money to sports to medicine to music, this is the age of the algorithm. The 2010 "flash crash" exposed our financial institutions' reliance on "trading bots" programmed by physicists and engineers. CIA analysts are being usurped by software that predicts what foreign leaders will do. Baseball general managers now trust their computers more than their gut instincts. Christopher Steiner traces the story of how algorithms (and their programmers) have spread from Wall Street to Main Street, altering every aspect of our lives. Sooner than we think, our schools, shopping choices, blind dates, and more will be governed by cleverly designed bots rather than human experience and intuition. Algorithms are already writing hit songs and selecting job candidates. In many cases these innovations are beneficial, such as bots that can interpret X-rays with greater accuracy than radiologists. But there will inevitably be troubling side effects, like the destruction of many professions and increased volatility in financial markets. Drawing on extensive research and investigative reporting, Steiner explores what our world will look like when computers make more and more decisions for us.