Flem, a Franco-Belgian psychoanalyst and author, takes a bit of a busman's holiday with this biography/critique of the 18th century's most famous rake. The 12 volumes of Casanova's History of My Life constitute one of the most delightful memoirs ever written. An elegant and witty- -and unexpurgated---1966 translation by Willard R. Trask finally became available in paperback this spring from Johns Hopkins University Press. So the timing of Flem's biography of Giacomo Casanova, the self-styled Chevalier de Seingalt, is fortuitous. Casanova was not, as he is casually styled, a mere libertine, a heartless and careless seducer of women. Rather, as Flem points out, he was a mercurial figure, a man of many guises--author, actor, soldier, priest, alchemist, scientist, gambler, lottery director, spy--who turned his life into ``an endless carnival.'' Most of all, he was a connoisseur of pleasure and happiness who dedicated much of his life to offering them to women. Yet he was, as Flem notes, ``born under the sign of loss.'' His greatest loves ended tragically, he outlived his closest friends, he was duped repeatedly by women. The Casanova depicted in Flem's book echoes the memoirs, which along with his letters are the main source for this volume. He sought out women who were his intellectual equals, placing a high value on exchanges of the mind as no less important than exchanges of bodily fluids. He is, Flem asserts, a lover of women in the best sense. Flem herself is, in Temerson's graceful translation, a skilled and passionate writer, as befits her subject. But her tone is darker and more elegiac than that of the memoirs and the result is not nearly as entertaining. Flem's book suffers from a peculiar organization in which Casanova's life is explored thematically rather than chronologically; those who are unfamiliar with his memoirs may find this volume opaque at times. A thoughtful and intelligent examination of the great lover, but more effective as analysis and literary criticism than as biography.