While standards and assessments demand that students be able to recall content information, planning guides direct teachers to prioritize the development of transferable skills and understandings, and scholars of education have spent the past century debating the purpose of history instruction without approaching consensus. The field is still divided as to whether the primary aim of history class is to help students accrue knowledge about their heritage, develop a skillset for inquiring about the past, or activate their desire to improve society. A teacher might reasonably wonder how they are supposed to teach students to think like historians, reflect like psychologists, and act like activists. In this article, Lightning Jay introduces the Document-Based Unit and argues that history teachers can help students engage with history at multiple levels through the thoughtful design of units.