During the brief periods between World Wars I and II that Matthew Josephson lived in Paris, he was one of the most colorful and involved American writers in Montparnasse. In the early twenties, as the controversial editor of Secession and Broom, Josephson became the high priest of American Dadaism, publishing the leading young writers among the avant-garde in the United States and France and championing from Europe an indigenous American art and literature reflecting the pace and tenor of the Machine Age. Several years later, after abandoning Dada and his Whitmanesque literary program, he returned to Paris to write what became a best-selling biography of Emile Zola. In the process his attitude toward literature and the role of the writer in society was dramatically transformed. Josephson would no longer lead the life of an apolitical aesthete pursuing art for art's sake; like Zola he would become a "writer...