This best seller offers an unparalleled look at the significant role that classroom discussions can play in teaching mathematics and deepening students’ mathematical understanding. Based on a four-year research project funded by the U.S. Department of Education, the second edition includes more examples of classroom talk focusing on pre-algebra and early grade levels; an expanded range of vignettes; chapter-ending discussion questions for book study groups; connections to NCTM’s Principles and Standards for School Mathematics; and an index of every mathematical and Standards for School Mathematics; and an index of every mathematical example used, classified by grade level and mathematical emphasis.