At my first A. L. A. conference, that of Waukesha, now eleven years ago, I heard discussed that topic ever fruitful of discussion: the librarian's attitude toward those books which are technically known as 'off-color.' The Indignant resentment of that part of the public which failed to appreciate the censorious solicitude of the librarian was vividly set forth, and there were those who felt that the only permanent way out was, in the words of George Ade, to "give the public what it thinks it wants." But the Librarian of Congress, in defending the library's point of view, uttered a remark which, as his remarks have a habit of doing, clarified the atmosphere as a Chicago lake breeze lifts a fog, and we settled back again serene in the knowledge that our orthodoxy had once more been vindicated and set upon its firm foundations. He said, in effect, that the duty of the librarian was not exclusion but selection and that in the full consciousness of his responsibility to the entire community he, the librarian, must exercise fully and freely his prerogative of selecting, out of the multitude of books, those which best suited his purpose and served his ends. The phrase "not exclusion but selection" struck at least one in that audience as so clear and telling a characterization of the librarian's business that he has kept it in mind, and well within reach for instant use, ever since. Many times it has served to confound the irate patron who combatively insisted that he was old enough to judge for himself what was good for him. Not a few times has it been the stone offered the facetious newspaper man who came seeking for bread in the form of a "story" on the "barring out" of the latest shady novel. Today it recurs again as a fitting text upon which to base a plea for the more effective advertising of books as to subject and scope, and I trust that my exegesis may not prove too violent to establish the relation between my text and my topic, which to my mind is close and intimate. A library, of the kind with which we are now concerned, is first of all--and after all--a collection of books, selected and assembled by the librarian. It may be so administered as to become a great civic force, a social instrument, an educational agency, but first of all it is a collection of units, brought together upon certain principles as they operate in the mind of the library's administrator. Now, the word "administer" is a transitive verb, one definition of which is: "to manage, to conduct, as in public affairs," and another, "to serve, to dispense, as in medicine." We may so administer--manage, conduct--the library as to render it a power for the advancement of humanity, and when we do that we are responding to the impulse which is generated in the very air which we in this age of advancement breathe.