This expanded and updated second edition is written for astronomers who want to learn more about how science education research is done and how to begin studying the teaching and learning of astronomy. It provides fruitful research designs and effective data collection and analysis strategies and points readers to avenues for publishing scholarly work in astronomy education research. The authors, long-time contributors to the astronomy education research community, provide rubber-meets-the-road guidance to both first-time and experienced researchers to get projects off the ground and into the scholarly literature.