Oriental drama has influenced twentieth century western drama in many ways. I have chosen to look at four ways that prove valuable in appreciating plays and productions of four western playwrights. Yeats's oriental influence took the form of conscious assimilation of elements of the Japanese Noh drama. Artaud was greatly influenced by Balinese dance-drama in the formation of his theory of theatre. His production of Les Cenci in 1935 was an attempt to make this theory work. Grotowski acknowledges an eastern influence but it is inalienable from the unity of his work. Brecht sensed the intellectual cohesion of the Noh in a partial translation, and finally achieved this in an ironic deviation from his incomplete source. The method of investigation is therefore different in each case. In looking at Yeats's Play for Dancers assimilated elements are listed and discussed, while in the case of Brecht the four stages in his development towards a cohesion analogous to that of the original Buddhistic source are examined. The Balinese dancedrama crystallised some ideas and catalysed the formation of others for Artaud; his theoretical writings and his recorded technique of direction in Les Cenci permit assessment of the extent of this influence. Finally the technique of training and performance of the Indian Kathakali is canvassed so that parallels and contrasts can be drawn with the work of the Polish Theatre Laboratory.