Anaxagoras was a man of one book; and that book, save for a few quotations in other authors and several summaries, is lost. A very potent and tantalizing book it must have been, to judge from all that we hear of it; the opinion of antiquity, preserved in Diogenes Laertius, was that its doctrines were expounded ‘in a pleasant and lofty style’, and the fragments which remain confirm this judgement. It was not merely a philosophical or scientific treatise; it was a work of art, in which the style rose and fell with the subject-matter.