History is a process. Just as science is the quest to discover and understand the truth about the world we live in, so history is the quest to discover and understand the truth about our world in the millennia that led up to this moment. These authors asked children who ranged in age from 6 to 12, first grade to sixth, how we know what happened in history. "We read it in our social studies book. "Some people in the family were there and they told us." "We read it in a book." "There are books about it." There was no indication in the answers that the students had any idea that historians today might look for and interpret evidence of the past. They were pretty convinced that somebody wrote history down when it happened, and we read it now. A deeper understanding of what the discipline of history is all about is reflected in the College, Career, and Civic Life Framework for Social Studies State Standards, or the "C3 Framework." The dimensions of the "C3 Framework's" inquiry arc are: (1) Developing questions and planning inquiries; (2) Applying disciplinary concepts and tools; (3) Evaluating sources and using evidence; and (4) Communicating conclusions and taking informed action. As students work with primary sources, they are participating in the act of inquiry. They are learning critical thinking skills that they will use all their lives, in college, career, and civil life. The authors provide seven strategies for teaching with primary sources: (1) Decide what you're looking for; (2) Determine the purpose and audience; (3) Look for bias; (4) Examine closely the source itself; (5) Find more information; (6) Consider your own role in the interaction; and (7) Compare a variety of sources. Working with primary sources is the best kind of training in critical thinking. Once students have learned to interpret and evaluate primary sources, they can use the same skills when listening to a news show, reading a book or magazine, or, perhaps most important, looking at the Internet. While they are learning about history and the world around them, they will also learn to be thinking, questioning citizens.