Büchner is the forerunner of expression, followed by Wedekind and Strindberg. The style is then traced from Kaiser and Toller to O'Neill, Wilder and the later O'Casey. In this 1981 book, epic theatre is studied from Piscator and Brecht to Dürrenmatt and Weiss, Arden and Bond, and is seen as flourishing in offshoots of documentary theatre.