Indianapolis Mayor Bart Peterson has laid down a bold challenge to the city's troubled public school system: improve or see your students migrate to the city's growing roster of impressive charter schools. This is no idle threat. In the 2006-2007 academic year, the mayor oversaw 16 charter schools serving 3,870 students. Peterson is currently the only mayor in the nation running a charter school authorizer out of his office and has proved himself willing to be judged by the results. What makes the mayor's experiment far more interesting than, say, improvements in the city's bus service, is that his charter schools are achieving results--in some cases, great results--with seriously disadvantaged kids. But charter schools per se were not the innovation that Peterson introduced to Indianapolis. Well before many researchers, let alone politicians or the media, had noticed that the key to good charter schools is a good chartering authority, Peterson and his education adviser David Harris began building what is now considered a national model of a charter school office. This article describes Peterson's campaign to bring charter schools to the city of Indianapolis and the structure of his charter school authority. (Contains 2 figures.)