Charter schools have become an increasingly significant aspect of the educational landscape. After a decade of implementation and research, this article returns to some of the original ideas underlying charter schools - including autonomy, accountability, and performance outcomes - to assess what progress has been made and what is still unknown. Although some successes are evident, there is still much to learn about the quality of charter schools and the experiences of charter school stakeholders. There is strong evidence that parents and students who remain in charter schools are satisfied and that charter schools are more autonomous than other public schools. But the jury is still out on some of the most important questions, including those about innovation, accountability, equity, and outcomes. This article provides a framework for examining research on charter schools and some guiding questions for future work.