In this short dissertation we have but little to do with the contents of any book. This knowledge can be acquired as circumstances and opportunity offer; we deal rather with extraneous details which are necessary to be known by everyone who aspires to form a collection of books for himself and would know something of the history of each. Every bibliographer, and also every collector of any eminence, has within reach certain books of reference which experience has shown to be absolutely necessary. Chief among these is Lowndes' _Bibliographer's Manual_ of which two editions have been issued. The first was published in 1834; the second in seven parts from 1857-61, with an appendix volume in 1864, having been re-issued from the stereotype plates without a date in 1871. The latter may frequently be picked up at auction sales for about 25s., but there is this peculiarity about the work, that it really would not seem to be very material which edition is purchased. The book is imperfect and full of errors: it cannot be relied on, and the second edition, which was edited by the late Mr. H. G. Bohn, the eminent bookseller, is as untrustworthy as the first edition. The original plan, which has never been departed from, was to give the names of English authors in alphabetical order, placing under each the title of the works he wrote, with the date of each edition, number of volumes, in many cases the collation, and finally the sums realised at auction. Nothing fluctuates so greatly as auction values, and it is not surprising, therefore, to find that not a single entry in Lowndes under this head can be accepted at the present day. Some of the variations between past and present prices are ludicrous in the extreme, and there is no doubt that anyone who attempted to obtain his knowledge of the value of books from Lowndes' _Manual_ would find himself in possession of a mass of old-time information which would be rather a hindrance to him than otherwise. The _Manual_ is useful because it gives a full and tolerably complete list of English authors, and collates many of their works with considerable care; it is, moreover, the authority quoted by cataloguers, and, being a copyright publication, practically bars the way to any rival work on the same subject. For these and other reasons it is indispensable.