Bertrand Méheust's *Un voyant prodigieux* reconstructs the life and reputation of Alexis Didier (1826-1866), a nineteenth-century French clairvoyant whose alleged abilities drew attention from contemporaries interested in mesmerism, occult phenomena, and the boundaries of scientific inquiry. Based on archival material, contemporary accounts, and a careful reading of the period's fascination with unusual mental powers, the book presents Didier as both a historical figure and a lens through which to examine how society interprets claims that challenge accepted explanations. Rather than treating clairvoyance simply as spectacle or credulity, Méheust situates Didier within the intellectual and cultural climate of his time. The narrative follows the circulation of his demonstrations, the witnesses who recorded them, and the debates they provoked. The result is a biographical and historical study of belief, evidence, and the persistent appeal of extraordinary claims in an age of emerging psychology and scientific classification.