This volume brings together 19 essays and introductions published by W.B. Yeats after 1912. Included among these is the long essay Per amica silentia lunae - in which Yeats first developed his important doctrine of the mask - widely admired for the luxuriant beauty of its prose. On the Boiler, filled with the deliberately contentious expression of Yeats's extreme opinions on society and culture in his last years, is another entry. Introduction to works by Shelley, Balzac, and the philosopher Bishop George Berkeley help to round out the collection.