A dry but well-informed account of the woman behind Mussolini's rise to power, by Cannistraro (History and Politics/Drexel University) and Sullivan (Senior Fellow/National Defense University). Margherita Sarfatti, an art critic and daughter of an influential Venetian Jewish family, was, according to the authors, a Svengali figure to the rough-hewn Mussolini. Beginning her affair with the future dictator (``My absurd lover, tyrannical and adored!'') in 1911, she became known as his ``inspiratrice,'' directing his reading (Proudhon and Machiavelli, among others), bolstering his belief in his greatness, and helping him to mold his vision of a new Roman Empire. Though an ardent socialist, Sarfatti supported Italian involvement in WW I, an action that got her expelled from the Socialist Party. After the war, she and Mussolini worked together to forge the Fascist Party from two unlikely allies, the nationalists and socialists, and watched their creation grow to power, nourished by conditions of mass unemployment, street-fighting, and demagoguery given credibility by electoral success. Sarfatti, the authors contend, had ``a far more flexible and inventive political imagination'' than Mussolini, and she was a central figure during these formative years—yet her affair with the dictator, and her influence, waned during the early 30's. In 1938, in the face of Il Duce's growing anti-Semitism, Sarfatti fled to Argentina with two suitcases full of jewels and modern art, treasures that she later parlayed into a position as one of the most important art collectors of the mid-century. She died in Italy in 1961. The authors devote too much space to Sarfatti's career as an art critic and promoter of Italian-American ties; still, hers is a remarkable, sometimes tragic, tale. (Photos.)