Book excerpt: This book on the teaching and learning of physics is intended for college-level instructors, but high school instructors might also find it very useful.Some ideas found in this book might be a small 'tweak' to existing practices whereas others require more substantial revisions to instruction. The discussions of student learning herein are based on research evidence accumulated over decades from various fields, including cognitive psychology, educational psychology, the learning sciences, and discipline-based education research including physics education research. Likewise, the teaching suggestions are also based on research findings. As for any other scientific endeavor, physics education research is an empirical field where experiments are performed, data are analyzed and conclusions drawn. Evidence from such research is then used to inform physics teaching and learning.While the focus here is on introductory physics taken by most students when they are enrolled, however, the ideas can also be used to improve teaching and learning in both upper-division undergraduate physics courses, as well as graduate-level courses. Whether you are new to teaching physics or a seasoned veteran, various ideas and strategies presented in the book will be suitable for active consideration.