These central supplemental libraries would be built up largely by a careful redistribution of existing resources. There is hardly a library of any size that does not contain many books which are very seldom used, books, however, which no librarian would dare to jettison, because he knows that some fine day a reader is sure to come along to whom one volume or another will be of priceless importance. There are many other books so infrequently called for that it would be an immense convenience to store them elsewhere, and utilize the valuable shelf-space for books in continual request. Books of this sort should be kept at the supplemental library, duly catalogued, and ready to be sent to any library throughout the area served, when readers require them. The supplemental libraries would, of course, be always buying more books; they would have to keep abreast of the latest advances in all subjects; but the works just described would form an important part of their original contents, and would be transferred to them free of cost. Local libraries are constantly put to the expense of buying books for one or two users; such users are, no doubt, among the most deserving of all their clients, and it is but just that their urgent wants should be satisfied. But it is a tax upon the capacities of small libraries that should be met somehow else; they would be spared it by the new system, and the cost of the supplemental library would be saved over and over again, the local library then having more funds to maintain the stock of books in regular demand.