The theories of Wagner and Nietzsche provide the basic principles for this volume, disseminated by the work of Appia and Craig, and affecting the later plays of Ibsen, Maeterlinck, and Lugné-Poe's Théatre de Le'Oeuvre. Jarry is seen as the precursor of surrealism; later symbolist elements are found in the plays of Claudel, Giraudoux, Yeats, Eliot, Lorca and Pirandello. Artaud's theatre of cruelty is related to the work of Peter Brook.

The theatre of the absurd is illustrated in Sartre, Beckett, Pinter and Ionesco. Recent avant-garde theatre in America and Britain also reveals elements of symbolism.