THE attempt to conceive imaginatively a better ordering of human society than the destructive and cruel chaos in which mankind has hitherto existed is by no means modern: it is at least as old as Plato, whose ''Republic'' set the model for the Utopias of subsequent philosophers. Whoever contemplates the world in the light of an ideal--whether what he seeks be intellect, or art, or love, or simple happiness, or all together--must feel a great sorrow in the evils that men needlessly allow to continue, and--if he be a man of force and vital energy--an urgent desire to lead men to the realization of the good which inspires his creative vision.