In commemoration of the 275th anniversary of the American Philosophical Society’s (APS) founding and birth of its long-time President, Thomas Jefferson (1743—1826), The Spirit of Inquiry in the Age of Jefferson assembles numerous scholarly publications and expert inputs that explore the history of science, knowledge production, and learning during Jefferson’s lifetime. In collaboration with the APS Library, the National Constitution Center, the Robert H. Smith International Center for Jefferson Studies at Monticello, and the Herbert D. Katz Center for Advanced Judaic Studies at the University of Pennsylvania, this rich and diverse collection covers myriad topics within science and religion during the mid-eighteenth and the early nineteenth centuries. Ranging from the transformative to the quotidian, this illustrated publication is a valuable resource to gain insights into an ever-changing and expanding early American republic.