The use of primary sources as texts in the classroom is growing. Teachers realize these vital witnesses provide opportunities to motivate students and improve learning. They bring students closer to the people, places, and events being studied and help students improve content knowledge while building skills. Recent trends in standards, such as Common Core, and the increasing use of the Document-Based Questions also promote primary source use. The strong push to use primary sources in teaching history and social studies creates a need among teachers for more information on what they are and how they can be used effectively in the classroom. Vital Witnesses meets this need by providing teachers with a comprehensive guide to primary sources and their use in the classroom. Primary sources are defined, and the various types are described. Classroom-tested activities and strategies are offered to teachers for addressing the needs of all learners and for accommodating Common Core standards and the C3 Framework for State Social Studies Standards.