I propose, in the following Essay, to trace the methods adopted by man in different ages and countries to preserve, to use, and to make accessible to others, those objects, of whatever material, on which he has recorded his thoughts. In this investigation I shall include the position, the size, and the arrangement, of the rooms in which these treasures were deposited, with the progressive development of fittings, catalogues, and other appliances, whether defensive, or to facilitate use. But, though I shall have to trace out these matters in some detail, I shall try to eschew mere antiquarianism, and to impart human interest, so far as possible, to a research which might otherwise exhaust the patience of my readers. Bibliography, it must be understood, will be wholly excluded. From my special point of view books are simply things to be taken care of; even their external features concern me only so far as they modify the methods adopted for arrangement and preservation; and I must dismiss the subject-matter of the volumes which filled the libraries of former days with a brevity of which I deeply regret the necessity. I shall point out the pains taken to sort the books under various comprehensive heads; but I shall not enumerate the authors which fall under this or that division.