Curriculum materials are among the most pervasive and powerful influences on school mathematics. In many mathematics classes, student assignments, the questions the teacher asks, the ways students are grouped, the forms of assessment, and much more originate in curriculum materials. At the same time, teachers have considerable latitude in how they use their curriculum materials. Two classes making use of the same materials may differ markedly in what mathematics content is emphasized and how students are engaged in learning that content. This volume considers a variety of research tools for investigating the enactment of mathematics curriculum materials, describing the conceptualization, development, and uses of seven sets of tools. Mathematics education researchers, curriculum developers, teacher educators, district supervisors, teacher leaders, and math coaches will find insights that can improve their work, and guidance for selecting, adapting, and using tools for understanding the complex relationship between curriculum materials and their enactment in classroom instruction. Following a preface, acknowledgments, and Introduction (Daniel J. Heck, Kathryn B. Chval, Iris R. Weiss, and Steven W. Ziebarth) the following contents are included: (1) Instruments Used by the University of Chicago School Mathematics Project to Study the Enacted Curriculum (Denisse R. Thompson and Sharon L. Senk); (2) Using Concerns-Based Adoption Model Theory to Develop Tools to Examine Variations in Mathematics Textbook Implementation (Mary Ann Huntley); (3) Developing Measures of Fidelity of Implementation for Mathematics Curriculum Materials Enactment (Daniel J. Heck, Kathryn B. Chval, Iris R. Weiss, and Steven W. Ziebarth); (4) The Development of Multiple Measures of Curriculum Implementation in Secondary Mathematics Classrooms: Insights From a Three-Year Curriculum Evaluation Study (James E. Tarr, Melissa D. McNaught, and Douglas A. Grouws); (5) Measuring Implementation of Instructional Materials to Support Conceptual Understanding and Accumulation of Knowledge (Jeanne R. Century Cassie freeman, and Mollie Rudnick); (6) A Tool for Analyzing Instructional Practices and Curriculum Materials in the Context of Specific Mathematics Learning Goals (Linda Dager Wilson and Jo Ellen Roseman); (7) The Surveys of Enacted Curriculum as a Measure of Implementation (Jennifer McMaken and Andrew C. Porter); and (8) Issues to Consider in Measuring Enactment of Curriculum Materials (Daniel J. Heck, Kathryn B. Chval, Iris R. Weiss, and Steven W. Ziebarth). A section about the authors is included.