A chronicle of ""what, for want of a better word, may be called socially conscious drama"" of the '20's and the '30's. Williams traces the theatrical motifs of the period from agitprop, political satire, expressionism, the breaking of the proscenium, to the development of ""meaning"" (that is, depth of character) in politically aware plays such as those of Odets, culminating, finally, in the Group Theatre's importation of Stanislavsky techniques. On Stanislavsky, Williams is lucid: it is not ""an infallible system,"" but rather ""a more or less orderly way of using certain tools of the craft."" He follows the development of the major companies: the Provincetown Players, the Theatre Guild, Prolet-Buhen, the Workers Laboratory Theatre, the Theatre Union, the Federal Theater Project, and the inimitable Group Theatre. Williams' elaborate apology for his book is somewhat disconcerting: ""My credentials. . . are the slenderest and most basic. . . I cannot promise the reader scientific accuracy. . . I am. . . unreliable."" In spite of his qualms, the work is competent, albeit not particularly erudite.