The biography traces the life of the chevalier d’Eon from provincial origins through a varied military and diplomatic career, including secret-service missions and embassies to Russia and London, to ultimate disgrace and litigation. It follows contested episodes—negotiations, quarrels with colleagues, publications, and pension arrangements—and the deliberate decision to assume feminine identity to regain public standing. Drawn chiefly from unpublished papers, letters, and official archives, the account reconstructs personal correspondence and contemporaneous testimony to explore issues of secrecy, reputation, gender performance, and the social and political circles of the period.