In 1644, the English physician and natural philosopher John Bulwer published a compendium of hand gestures. He called gestures the most natural language of humanity, following Francis Bacon’s description of gesture in The Advancement of Learning (1605) as having a natural, rather than conventional, “affinity” with the things signified. Chirologia details a variety of manual gestures—including handshapes still used in British sign language—in text and image from literary, theological, Biblical, and medical sources, and argues that gesture is the universal language of reason and human communication that endured through the differentiation of spoken languages after the Biblical flood. All verbal languages are derivations of the more basic language of gesture, Bulwer argues, which mimics the movements of the sense organs in universally understood “speaking motions.”