This book is basically a scholarly analysis of the meaning of Yeats' five last plays and some lyrics which are related to them in meaning. The plays based on the structure of Japanese plays are chiefly The King and the Great Clock Tower, The Death of Cuchulain and a few others, all notable chiefly for their obscurity. The keys to the obscurity, Mr. Wilson claims and abundantly proves, lie in the knowledge of Yeats' symbolic sources -- his deep immersion in subjective mysticism, his familiarity with Plato, neo-Platonism, the Jewish Kabbala, alchemy, Buddhism, Indian philosophy and Celtic folklore. Mr. Wilson takes the works under consideration one by one and line by line and traces the imagery and symbols to their sources. What makes this procedure acceptable is that Wilson never claims that Yeats' poems- for the most part- cannot be read and enjoyed on a certain level because of their exquisite rhythms and inspired used of words, without all this reference to scholarship. What he makes quite clear is that a deeper knowledge of the processes of Yeats' mind doubles the enjoyment of his poetry. Subsidiary to this analysis is the deduction to be made from it that Yeats is a poet of universal appeal, combing (as Malraux has done for art) elements as disparate as the Japanese, the Celtic and the Egyptian. This is the modern note:- it is in combination with Yeats' almost Jungian belief in the self that makes him the greatest poet to speak for modern man. An important addition to Yeats' scholarship, with an added appeal to the modern concern in myth and symbolism.