I became intensely interested in Dragon Worship and the Dragon Myth during my recent journey in China and Mongolia in support of the Central Asiatic Expeditions of Roy Chapman Andrews. Especially, in the royal city of Peking appears the apotheosis of the Dragon in every conceivable form of symbolism and architecture. The Dragons leading up to the steps of the temples and palaces of the Manchu emperors, and the superb dragon-screen guarding the approach to one of the royal palaces, are but two of the innumerable examples of the universal former belief in these mythical animals, and of the still prevailing beliefs among the common people of China. For example, one night in a far distant telegraph station in the heart of the desert of Gobi, I overheard two men pointing out Leader Andrews and myself as `men of the Dragon bones.' On inquiry, I learned that our great Central Asiatic Expedition was universally regarded by the natives as engaged in the quest of remains of extinct Dragons, and that this superstition is connected with the still universal belief among the natives that fossil bones, and especially fossil teeth have a high medicinal value. Not long after my return from Central Asia, I suggested to my friend, Ernest Ingersoll, that he write the present volume, preparing a fresh study of the history of the Dragon Myth which, now largely confined to China, once spread all over Asia and Europe, as dominant not only in mythology but entering even into the early teachings of Christianity, as so many other pagan myths have done. I knew that the author was well-qualified for a work of this character, because of his remarkable success in previous volumes for old and young, and in his original observations on various forms of animal life, from the American oyster to many birds and mammals. He is especially versed, perhaps, in regard to one very interesting question which is often asked, namely, how far the animals of myth and of legend, like the Dragon, the Hydra, the Phoenix, the Unicorn and the Mermaid, are products of pure imagination, and how far due to some fancied resemblance of a living form or to the tales of travelers. For example, it occurred to me, while examining the giant fossil eggs of the extinct ostrich of China (now known under the scientific name Struthiolithus, assigned by the late Doctor Eastman), that it may have given rise to the myth of the Phoenix or of the Roc.