It may be indifferently written, but the Josephson memoir is just about the biggest and bounciest earful of what life was like among the 1920 Parisian exquisites and expatriates to have hit the stands since Malcolm Cowley's celebrated Exile's Return. Everybody who was anybody is here: Eliot, Hemingway, Cummings, Eluard, Cocteau, Pound et al. And author Josephson with almost total recall resurrects the era's razzle-dazzle: little mag manifestos, cafe battles, telepathy, Chaplin 2-reelers, Negro jazz, drugs, bardellos, parodies, polemics and piles of bourgeois Papas' money. Dizziest episode: the wild Dada stretch during which total -subversionist Breton straps 2 pistols round his head, Chirico paints the ""meeting of incompatibles"" and de Sade's ""beautiful crimes"" become the rage. Most distressing: Hart Crane's troubles back home in the States, and the author's own glum Wall Street adventures. A grand, gossipy guide to the 20th century's most inimitable and irreverent days.