With the obliging assent of Messrs. Adam and Charles Black, about thirty pages of this Volume, chiefly in the Introductory Chapters, have been reprinted (with needful alterations) from the article Libraries, in the last edition of the Encyclopædia Britannica.

Those thirty pages excepted, the contents of the present Volume are now published for the first time, and have been, in large measure, based upon documents heretofore unused, and upon personal examination of the principal Collections which are described.

It follows that the present Volume—the Introductory Chapters excepted—occupies ground which was but touched on in Memoirs of Libraries (1859). It is at once a new and independent work, and a continuation of the preceding work on the same subject. Should it be favourably received, it will be quickly followed by another new volume specially devoted to The Founders of the British Museum, based on original researches, and much of which is already prepared.