Modern theatre, at an ""impasse between realism and avant-garde experiment"", is the subject of this long, detailed, and very interesting work. While the Nineteenth Century affirmed realism only to avoid it in practice, the Twentieth disavows it but manages to keep it intact anyway. So goes the thesis. Mr. Gassner then calls for new understanding, new creative and interpretive writing to save the theatre from becoming the ""Vanity Fair"" he considers it now to be. Miller, O'Nell, Williams and Giraudoux come under particularly close scrutiny, as do seventy recently performed plays of the last ten years, which are here discussed and appraised. Challenging in theory, stimulating in presentation, and useful as one type of compendium of all that the theatre has been doing of late.