Any reader should be allowed to use any book in the library when and where it is most convenient to do so, so far as this can be done and preserve the rights of other users and preserve valuable materials not easily replaced for future generations of users. The ability to shift any book from the place where it is little needed to the place where it is much needed, at a moment's notice, is the ideal. Users may be roughly grouped as follows: 1. Instructors of all grades, those whose need for books is primarily for teaching. 2. Those doing research work, which class may include teachers, graduate and undergraduate students. 3. Students needing books for collateral reading. 4. General readers of all classes, and all persons are general readers when not reading for a definite purpose, but for general culture. Obviously the rights of all these classes are not of equal importance. To outline the means of protecting their rights, it is necessary to classify users by certain of their characteristics which bear no relation to the groups named above. First, the conscientious worker who, while using many books, never retains one beyond his real need for it, and who constantly bears in mind the possible need that others may have for a book he is using. Library rules are not made for such. The next and most difficult class to deal with are those who want to gather about them all the books they can conveniently lay hands on, with the thought, that they will "come handy some day." A large class, running down to the lowest ranks of college students, comprise those who think they must have all the material on a subject at hand at one time. Another class, largely college students, is made up of those selfish persons who, having a task, ride rough shod, if necessary, over the rights of others in doing it. Then there is the small class that can be designated by no other names than thieves and vandals, those who steal books, and cut out text or illustrations. An adequate code of rules and regulations should be drawn up, care being taken that all rules should be made for the sole purpose of preserving rights and property. Of first importance are the regulations for getting books back into the library. A time limit of one month on all books not in use for instruction or research has been fairly successful. All bound volumes of periodicals may be limited to two weeks or one month. A limit may be put on the number of volumes a user may have out at any one time. A requirement that all books must come back to the library, once a year, regardless of the use being made of them, will keep in the library many books that have been left lying around after being used.