An extended inquiry into human credulity and scepticism opens with reflections on how belief and doubt influence knowledge. The essays survey historical forms of imposture, ranging from ritualized oracle practices and manufactured miracles to prophetic pretenders and popular delusions, and catalog the social and theatrical techniques deceivers employ. Attention is given to the likeness of error to truth, the contagious spread of excitement and imitation, and practical stratagems used to exploit trust. The collection closes by tracing the gradual advance of more rational inquiry while acknowledging persistent superstitions and contemporary examples of charlatanism.