When Sports Illustrated declared on the cover of a June 2014 issue that the Houston Astros would win the World Series in 2017, people thought Ben Reiter, the article's author, was crazy. The Astros were the worst baseball team in half a century, but they were more than just bad. They were an embarrassment, a club that didn't even appear to be trying to win. The cover story, combined with the specificity of Reiter's claim, met instant and nearly universal derision. But three years later, the critics were proved improbably, astonishingly wrong. How had Reiter predicted it so accurately? And, more important, how had the Astros pulled off the impossible?