This policy report provides an overview of the Common Core State Standards, how they were developed, the sources that were referenced in their development, the need for educational standards generally, what they entail, and what it will mean for educators to implement them. The report draws from research and reference material to outline the argument for the Common Core and the sources used in its development. These include college and career readiness standards developed over the past 15 years, high quality state standards, and the content specifications from other nations whose educational systems are widely respected. Additional research demonstrates the relationship between the Common Core and college and career readiness. While this report does offer insight into the structure of the standards, most of the information presented here is designed to help policymakers, educators, and other interested parties understand the effects on educational practice. [This document includes two commentaries: (1) "Tracking Common Core Implementation in California" (Andrea Venzia); and (2) "Common Core for All--Reaching the Potential for Students with Disabilities" (Martha L. Thurlow).]