The book compares the standardized test scores of both elementary and high schools charter schools with the scores for regular public schools located nearby. It examines the position supported by charter school advocates that charter schools should be supported because they outperform regular public schools. Given that charter schools in Chicago have enjoyed a great deal of support from the past two mayors, and that they make up some 20% of all public schools in the city, Chicago is the perfect location in which to examine this critical issue. Charter schools siphon money and in theory better students from regular public schools at a time when public schools in almost every big city faces financial difficulties. Teachers unions oppose them, as do most liberal scholars. Conservatives and big business support them, as do most conservative scholars. The existence of charter schools is a most divisive issue Yet, little real data exist to allow us to properly judge the effectiveness of charters. The current work changes that by examining test data in a sophisticated manner that allows comparisons between charters and regular schools. This work should move the debate forward, but will no doubt generate controversy as well.