The public libraries deem themselves the allies of formal educational processes; but also the direct educators of that part of the community not subject to the formal processes. It is this latter responsibility which has led them to attempt a broader service than the mere supply of books. A book is not the only nor necessarily the most effective vehicle for conveying knowledge. There are illustrations which more directly convey an impression, and often as fully state a fact. And photographs and process reproductions are now part of the equipment of a public library almost as conventional as books. Within the past year 10,000 such have been added to the collections of the Boston Public Library; not as works of art (they are for the most part cheap silver prints and the Art Museum is but a hundred feet distant); nor merely as aids to the study of the fine arts and the useful arts, but also as convenient auxiliaries to the study of history, of literature and institutions. And they are used by individuals and by classes not as a substitute for the text, but as helping to render vivid the lesson of the text. With these go lectures in exposition. Every building of importance recently designed for the uses of a public library includes an art gallery and a lecture hall. What an immense augmentation of function this implies! It implies that the library is no longer merely an aggregate of books, each passive within rigid limits; but that it is an active agent having under its control material which is kept plastic and which it moulds into incredibly varied shapes to suit incredibly varied needs.