=Reference Books.=—In helping to answer an inquiry or to find material on a subject, the first question in the mind of the reference assistant should be, not where, or in what particular book, shall I find the information, but rather: In what kind of a book, or in what class of books? While it is necessary that the assistant should early become acquainted with the most important or most convenient works of reference on the various subjects of general interest it is especially desirable to know the point of view of the inquirer, and what sort of books, whether reference or research, will be needed. Reference books—meaning ready reference books—may be generally divided into two great classes: Dictionaries and Encyclopedias. The first includes those works which treat of words used as language; their meaning, history, pronunciation and use. The second class treats of subjects, such as countries, men, animals, sciences, arts, trades and substances; their character, history, distribution, etc. In both of these classes the arrangement of the matter is generally alphabetical. The term “dictionary” is frequently used for a cyclopedia of a special subject, as in the case of dictionaries of biography, antiquities and architecture. Books of facts, almanacs, yearbooks and census returns, belong to this class. Of the general, or universal encyclopedias, devoted to all classes of subjects without regard to country, age, or character, every public or school library, no matter how small, should have at least one, and the larger libraries should possess several, as they differ considerably in their treatment of the subjects. Encyclopedias published in the United States, England, France and Germany, while treating of matters of interest in all these countries, would naturally favor their own nationality and include subjects in which their immediate readers would be most interested. A third class, to which the general name of bibliography is usually given, includes not only the indexes to the literature of a subject but catalogs of libraries, special collections, selected lists, etc. Frequently these are the books to be consulted first, as they direct the searcher to works and articles of far more importance than any of the general ready reference books. One of the most important and useful books with which the reference assistant should become acquainted is Miss Kroeger’s “Guide to the study and use of reference books,” (A. L. A. Publishing board, 1908; Supplement, by Isadore G. Mudge, 1910). It is divided into classes by formal subjects, but the annotations to the titles included are generally sufficient to show the character of the works, and to what kind of needs they would be best adapted. The Michigan State board of Library Commissioners has published a handy “Annotated list of reference books for school and public libraries,” 1910, which will be found useful by those in charge of smaller libraries.