This is a music book. A new work on Wagner requires some justification. It might be urged that, since the Meister has been dead for some decades and the violence of party feeling may be assumed to have somewhat abated, we are now in a position to form a sober estimate of his work, to review his aims, and judge of his measure of success. Such, however, is not my purpose in the following pages. I conceive that the endeavour to estimate an artist's work involves a misconception of the nature of art. We can estimate products of utility, things expressible in figures, the weight of evidence, a Bill for Parliament, a tradesman's profits. But a work of art is written for our pleasure, and all that we can attempt is to understand it. True, we must judge in a certain sense, we must weigh and estimate before we can arrive at understanding; but it is one thing to meditate in the privacy of one's own mind, quite another to publish these constructive processes as an end in themselves, to set up critical 'laws' and expect that poets are going to conform to them. Art, says Ruskin, is a language, a vehicle of thought, in itself nothing. Plato's teaching in the third book of his Republic is the same, and the idea of the secondary nature of art, of its value only as the expression of something else, of a human or moral purpose only fully expressible in the drama, is the nucleus of all Wagner's theoretical writing. In private conversation and in his letters he often spoke very emphatically'.I would joyfully sacrifice and destroy everything that I have produced if I could hope thereby to further freedom and justice'.