As you read this book it is already moving out of date."" The thesis of an energetic experimenter, Britain's renowned director who triumphed most notably here with Marat/Sade. Mr. Brook divides his theatre into four very general arenas -- ""Deadly"" (traditional, the confined archaic past), ""Holy"" (the ultimate, trans-""Happening""), ""Rough"" (The Theatre of Cruelty in which he played a major part) and ""Immediate"" (the theatre of now, today's tools in process of transfiguration). He is pro-critic, himself haranguing the ""sloppy"" haphazard training of actors with misunderstood Method, less technical competence. He despises the proletarian pick-me-ups spoonfed to indifferent audiences and all the usual accoutrements from Broadway to the West End. High praise here for the visionary theatre of Artaud, the trials of Brecht, Beckett, Genet, Pinter and any impassioned seeker-after-total-environmental theatre such as ""The Living Theatre."" For all of his rhetorical soothsaying, his search for a metaphysical poetics, Mr. Brook only once touches a core asking ""what are we searching for anyway,"" with Happenings that are lackluster ""Do-it-yourself Zen,"" Absurdity that heightens only surface truisms, Cruelty that bores. He does not have the answer but his approach and suggestions for exercises and working relationships as a Director substantially fill an Empty Space.