Teaching controversial social issues can be a daunting, and oftentimes terrifying, prospect for social studies teachers. In many ways, this fear is warranted given the politically polarized nature of American society in the 21st century. However, effective social studies instruction requires that students begin to grapple with difficult issues in tolerant ways. The chapters in this book, many of which are written by leading scholars within the field of social studies education, cover a range of 21st century social issues, including politically volatile issues such as gun control, marriage equality, the Black Lives Matter movement, and immigration. This book offers both a theoretical justification for engaging students with controversial social issues and practical suggestions for how to successfully implement discussions of these types of issues in K-12 classroom settings.