The titans and lotus eaters of the 1920s are captured in this extraordinary and very readable literary document.   Harold Loeb’s second novel recounts his experiences after the now-legendary 1925 Pamplona Fiesta (he is the original of Robert Cohn in Hemingway’s The Sun Also Rises). When he met Hemingway, Loeb had already had his first novel, Doo­dab (1924), accepted, and had come to know Malcolm Cowley, Ford Maddox Ford, James Joyce, Gertrude Stein, and Ezra Pound, among others.   The Professors Like Vodka (1926) is the story of two American university professors who discover the Caveau U­kranien in Montmartre, meet the glamor­ous Vera, Countesse Adranova, and Cléo­pâtre, daughter of a Russian General, and guided by the Russian women discover a new and exotic Paris, filled with gaiety, romance, and the bittersweetness of love.   In the Afterword written for this new edition, Loeb recounts the circumstances of his writing of the novel and his subse­quent career in Paris and in the United States. Mr. Loeb now lives in Weston, Connecticut.