Background/Context: As implementation of the Common Core Literacy Standards moves ahead, teachers, students, and schools are discovering that the standards demand a great deal of them in order to achieve the vision of college, career, and citizenship in the global-digital world outlined in the standards. To accomplish the goals and high expectations set forth in the Literacy Standards, teachers confront fundamental changes in their curricular, instructional, and assessment practices. Purpose/Objective/Research Question/Focus of Study: This article presents a working model of the formative assessment process that we think will be essential for effective implementation of the standards. Assessment for learning rather than testing of achievement is presented as a way of guiding teachers and students through the progressions needed to college and career-readiness. The paper is organized around four points: (1) the distinctive features of the model, (2) the match between the model and the vision of the standards, (3) a description of the inquiry process that serves as the "engine" for the model, and (4) an account of the Herman-Heritage cycle-time/grain-size concept that supports ongoing management of formative assessment. The model is designed to be embedded in the project-based activities called for in the standards as students conduct short- and long-term research across the disciplines. Research Design: This article presents the results of a careful and comprehensive reading of the Common Core Literacy Standards. A focused review of the literature on formative assessment serves as the foundation for the working model presented here. Conclusions/Recommendations: The conceptual ideas and practical tools discussed in this article point to the need for substantial and sustained professional development, both preservice and inservice, to support the fundamental changes entailed by the standards. To foster the deep understandings called for by the standards, teachers will require an equally deep understanding of formative assessment as a process in which inquiry is embedded in instruction to monitor learning, provide feedback, and shape students learning as it is taking place.