It has not been ascertained when or by whom its present title was imposed on this book. We find early writers quoting its teachings as those of Hwang-Lao (黃老), that is, of the Emperor Hwang and Lao-tzŭ. The former lived, or is supposed to have lived, about B.C. 2600, and some parts of the Tao-tê ching are expressly ascribed to him, for example, Chapter VI is quoted as his.[3] Another title under which this book is referred to by old authors is Lao-tzŭ-shu (老子書), that is, the writings of Lao-tzŭ,[4] and it is not until the time of Emperor Wên (文帝) of the Han dynasty, or about B.C. 160, that we find the term Tao-tê used. We must remember also that the use of these two words does not indicate that the book treats only of what is meant by them,[5] nor are we to imagine that the former part of the work refers exclusively to Tê. The first word of the former part of the book is Tao, and the first important word of the latter portion is Tê, and these two were simply combined in order to form a designation for the whole, according to the usual Chinese custom.[6] Hiüan-tsung (玄宗), an Emperor of the Tʽang dynasty, who reigned in the early part of the 8th century of our era, besides several other innovations, gave a separate name to each part of this book, calling the former part the Tao-ching and the latter the Tê-ching.[7] These appellations, however, are seldom, if ever, used, and the work is now universally known as the Tao-tê ching. From the words of Confucius it might even with some degree of probability be inferred that already in his time the name Tao-tê was used, the term Ching or classic, being, of course, a much later addition and given by way of respect. From the naming of the book I now proceed to the considerations of the way in which it has been divided. Szŭ Ma-chien simply says that Lao-tzŭ made a book in two parts, containing more than five thousand characters, and setting forth the signification of Tao and Tê. Chʽao, however, says that the work contained 5,748 words in eighty-one chapters. The original division was probably only one into two parts; afterwards, however, these were subdivided into chapters. The number of these latter composing the entire book varies considerably.[8] Some editors make fifty-five chapters; some make sixty-four; some, and notably Wu-chʽêng, make sixty-eight; and some seventy-two. The most usual number, however, is eighty-one, and this is said to be sanctioned by the old and venerable authority of Ho-shang-kung (河上公) of the Han dynasty. The Taoists are very fond of the number three and its multiples, and this particular multiple, eighty-one, is associated in tradition with Lao-tzŭ’s birth and the years of his life, and there is perhaps no greater reason for preferring this to any other division.