Women of dubious reputation not only animate history's calender of rise-and-falls, they also proffer a never-failing fascination to errant biographers of later times. Even eighteenth-century England, sometimes known as the ""Age of Reason,"" had its own highly unreasonable object of gossip in Elizabeth Chudleigh, a notorious woman with aspirations of grandeur. Starting as penniless country maid with bodily assets and the nerve to utilize them, Miss Chudleign ended up the wealthy wife of two poers at once. An early marriage kept secret, she proceeded in her notorious affairs as a ""Maid of Honour"" at the Court, and finally, after twenty illicit years with the Duke of Kingston, she managed to legalize her title as ""Duchess."" Scandal, never far behind her, unearthed the first marriage and, just as she had become a ""Lady of Distinction"" with her loved jewels and property, she came to trial for bigamy and the possible loss of title and wealth. Even her popularity with the high- on the continent -- from the Electress of Saxony to Russian Czarina Catherine and Frederick II of Prussia -- could not extricate her from the immoral morass. Fortunately for the ""unduchessed"" Duchess, the Duke died, followed soon after by her first husband, who had the grace to became a Count before he left. A legal countess with a Duke's riches, Elizabeth Chudleigh ended her life, self-exiled, in France. Mention of her finally ceased to appear in Horace Walpore's letters. Very well-written, the biography is competent -- and with materials like Chudleigh, a readership is guaranteed. Ancient eccentricites exhumed.