In searching for alternatives to multiple choice tests and document-based questions, the authors were inspired by the common practice of "do-nows" (also known as "bell work") in which teachers give students a brief task at the beginning of class to prepare them for the day's lesson. Could these minutes at the start of class be used for formative assessment? With support from the Library of Congress, they set out to create tasks that would give social studies teachers new options. The exercises are built around primary sources from the Library's extensive collection. Each exercise assesses core skills of historical thinking and provides teachers with quick feedback about student understanding.