The theme of this book is that classroom assessment (CA) can and should be viewed as a unified endeavor, wherein teachers and students obtain, interpret, and use information about knowledge and skills to help learning progress. Used systematically, CA processes begin prior to instruction and happen continuously as teaching proceeds. They guide student and teacher planning, instructional decisions in the moment, and interpretations of the accumulated learning of students over the course of time. In this text, we describe a system of classroom assessment that we have developed based on learning theory, our own research, and years of experience in K–12 and teacher education: the CA:SRL framework.