The book is designed to show, in three great movements representing birth, growth, and perfection, the evolution of the human spirit in the world. The spirit, which is here synonymous with love, is traced from the instant which is chosen to mark its birth (the awakening sense of beauty in primitive man), through its manifold states of excess and defect, up to a transcendent union which draws the dual powers into a single ecstasy. The greatness of the central theme is matched by the dignity of its presentment, while the dramatic form in which it is embodied saves it from mere abstraction. We see the dawn of the soul in the wolf-hunter, suddenly perceiving beauty in nature and in women: the vindication of the soul by Vashti, magnificently daring to prove that it is no mere vassal to beauty: and the perfecting of the soul in the terrible paradox of Judith's virginity. But it is in one of the closing pieces, called fittingly "The Eternal Wedding," that the poet attains the summit of his thought along these lines; prefiguring the ultimate union of the conflicting powers of life in one perfect rapture. ... I have Golden within me the whole fate of man: That every flesh and soul belongs to one Continual joyward ravishment ... That life hath highest gone which hath most joy. For like great wings forcefully smiting air And driving it along in rushing rivers, Desire of joy beats mightily pulsing forward The world's one nature.... ... so we are driven Onward and upward in a wind of beauty, Until man's race be wielded by its joy Into some high incomparable day, Where perfectly delight may know itself,-- No longer need a strife to know itself, Only by its prevailing over pain. That is the topmost peak that his philosophy has gained--for just so long as to give assurance that it exists. But no one supposes that he will dwell there: it is altogether too high: the atmosphere is too rare. It was reached only by the concentration of certain poetical powers, chiefly speculative imagination, which carried him safely over the chasms of a lower altitude. But when other powers are in the ascendant, as for instance in _The End of the World_: when he is recalled to actuality by that keen eye for fact which is so rare a gift to genius of this type, the terror of those lower chasms is revealed. Here is one of the characters reflecting on the thought of the end of the world, which he believes to be imminent from an approaching comet: