THE purpose of this work is to exhibit clearly and with sufficient fulness the general characteristics of Aryan mytho- logy, as a systern which has grown up from words and phrases denoting not one or two objects only, as the sun or moon, but all the phenomena of the sensible world, as they impressed themselves on the minds of primitive men. It has not been my object to give an exhaustive account of the myths of every branch of the Aryan race. To ascribe equal value and interest to the traditions of all the tribes included within the great Aryan family would indeed be absurd. But in the present edition I have given to the Slavonic mythology, and to some other subordinate topics, as much space as the con- ditions of my subject enabled me to afford.

WITH a deep consciousness of its shortcomings, but with a confidence not less deep in the security of the foundations laid by the Science of Comparative Mythology, I submit to the judgment of all whose desire it is to ascertain the truth of facts in every field of inquiry a work on a subject as vast as it is important. The history of mythology is, in a sense far beyond that in which we may apply the words to the later developements of religious systems, the history of the human mind; and the analysis which lays bare the origin and nature of Iranian dualism, and traces the influence of that dualism on the thought and philosophy of other lands, inust indefi- nitely affect our conclusions on many subjects which may not appear to be directly connected with it.