The total number of students in the United States attending online and blended schools is unknown. A reasonable estimate is between one and two million students, or roughly 2-4% of all students in the country. More than half of all states allow online schools that draw students across district boundaries; perhaps 350,000 students attend these schools. Other students in this study are attending online schools that serve students within a district or sub-state region, blended charter schools, and alternative education programs. Many of these schools are charter schools, and others are operated or authorized by school districts, intermediate units such as Board of Cooperative Educational Services (BOCES) and County Offices of Education, and other organizations such as juvenile court schools. This report focuses primarily on why students choose online or blended schools. Also included in the report are brief profiles of five schools, from different regions of the country, that demonstrate different online and blended learning instructional models. [Co-published with the Foundation for Blended and Online Learning. Foreword by Amy Valentine.]