The number of sciences included in the term “bibliography” probably reached its zenith with Gabriel Peignot, a noted French bibliographer of the last century. In his enthusiasm for the subject he arrogated to bibliography a knowledge of such subjects as philosophy, logic, philology, history, mathematics, geography, etc., in addition to typography, the composition of books, material and literary, and all that appertains to the books themselves. In short, bibliography was to him the _scientia scientiarum_. Peignot’s English contemporary, Thomas Hartwell Horne, _1780-1862_ gives a more concise definition in his “Study of bibliography” (_1814_) but he errs in the same manner, though in a lesser degree by claiming for bibliography an encyclopædic knowledge of the history, values and contents of books. The modern tendency for specialisation renders such erroneous conceptions of the subject impossible, for palæography, typography, history, etc., rank as distinct topics, though, of course, they will always be correlated. Many attempts have been made in recent times to give a concise definition of what is understood by the term “bibliography,” but there is little uniformity of opinion, and much confusion. The confusion is undoubtedly caused by the application of one term to what should remain distinct studies. The subject now resolves itself into two standpoints--the historical-and-dilettante; or, the practical-and-utilitarian. Historical bibliography to the general public is yet very vague in its limits, it includes the history of printing, book-collecting, study of the rare and curious in books, etc.; but among experts it is slowly and surely being limited to the history of printing, and in the future the historical side of bibliography will be known as the “history of printing.” When this understanding comes to pass “bibliography” can be applied to what is now known as “practical bibliography,” which is defined by the late J. D. Brown in his “Manual of bibliography” (_1906_) as “the science which treats of the description, cataloguing, and preservation of books.” The word “bibliography” is also applied to the literature of a subject, but in this sense there is little likelihood of confusion as it is generally used in conjunction with another topic, as, “A Bibliography of Cotton Spinning.” (_2_) KINDS OF BIBLIOGRAPHY. There are six recognised classes of bibliographies:-- _1._ General Bibliographies--Books not limited to those of any period, locality, author, or subject, _e.g._ Brunet’s “Manual du Libraire.” _2._ National Bibliographies--Books printed in a given country or about a given country, _e.g._ “The English Catalogue of Books.” _3._ Trade Bibliographies--Books in print or on sale by publishers, with full particulars as to size, price, pages, etc., _e.g._ Whitaker’s “Reference Catalogue of Current Literature.”