This statement of first principles was made by Melvil Dewey at the Second International Library Conference, held in London, July 13-16, 1897, and is reprinted from the Transactions and Proceedings of the Conference (London, 1898). In reading this address, it must be kept in mind that it was made to Englishmen, whose conception of the functions of a public library were then, as now, much more conservative than ours. A sketch of Dr. Dewey will be found in Vol. I. of this series. We have been listening to an admirable account of the development of the library movement from earliest times to the present day, and I venture to believe that when the history of the age in which we live is written, and is looked back upon by those who shall come after, it will be known distinctively as the "Library Age." Libraries of one sort or another have existed from the beginning of human history, and we are now well into the fifth century since the invention of printing; so that it would seem as if there had been abundant time for library development. But so great an institution as the modern library is of slow growth. It has taken a thousand years to develop our school system from university down to kindergarten. The public library is much more rapidly going through corresponding stages in order to come to its own. The original library was a reservoir, getting in and keeping safely, a storehouse for posterity. That was and is a great function, for which I have profound respect. Then, after many centuries, came another library epoch, for which we all feel still greater respect. The cistern was made a fountain; giving out was seen to be more important than getting in. The library is no longer merely a passive receptacle, but becomes an aggressive educational force in every community. The reservoir will not become a stagnant pool, for, in its branches and deliveries, the public library has mains and pipes laid through every street, and reaching almost to the door of every householder. And we live now not in the age of the reservoir, but in the age of the fountain. In our zeal and admiration, however, we are apt to forget that there is yet another and even more important stage to reach. In my own city, some time ago, we spent half a million dollars in providing an ample supply of water. But we found that we had really opened convenient communication with the cemetery by water, for the quality of the new and abundant beverage was such that our death-rate steadily rose. The burning question became qualitative, not quantitative, and we are now spending our money on efficient filtration. Of course no library intends to circulate injurious books, but equally no town intends to distribute harmful water. We are concerned more with the results than with the intention. The mortality tables make plain the physical defect, but alas! science has as yet devised no instruments