This book provides data and uses stories and personal insights gleaned from nearly 6, 000 observations in real classrooms across the nation. The mix of data and descriptions provide a clear picture of the rich interaction of teacher and student behaviors and how one predicts the other. Graphs and tables provide concrete visual representations of the often surprisingly low rates of effective instructional practices used in the average classroom. In addition to a description of how the large dataset was developed, there are descriptions of what it is like to visit multiple classrooms in different schools, what the data tells us about teaching and learning in our public school system, and what the implications are for pre-service teacher training, school professional development, research, and understanding interaction effects.