Gertrude Stein and Virgil Thomson are known as much for their formidable egos as for their contributions to twentieth-century arts. That either could collaborate intimately with anyone is surprising. Yet Stein and Thomson did work together, magnificently so, most notably on the landmark opera Four Saints in Three Acts and the fanciful The Mother of Us All. This annotated collection of correspondence reveals the spark that existed between the two American masters over the course of their sometimes rocky friendship. The roughly 400 letters written between 1926-1946...