=339. Lettering and Numbering.=--When lettering and numbering have to be done apart from the re-binding, they can be executed by the staff after a little practice, as pointed out in Section 335. The object of lettering is to facilitate the finding of books, and for this reason it should be clear and bold. It is also possible by means of a little variation to obtain a certain amount of class-guiding in the system of lettering, and it should be made an invariable principle in every public library to adopt a certain order of particulars on the backs of books, and stick to the order. Too often this important matter is left to the fitful fancy of the binder’s finisher, with the result that very frequently the author’s name appears in all the panels in rotation. The series of suggestions given in Fig. 127 for dealing with each class is offered as a basis on which any librarian can build a system of his own. The letterings are arranged to provide for titles, authors, volume numbers, class numbers, and dates of publication when necessary. Class letters and numbers occupy one definite place on each book, which is not subject to variations in height when appearing on books of different sizes. The markings here figured for the backs of books are arranged so that titles occupy the leading panel in all classes and thereby correspond with the great majority of the books as issued by publishers. [Illustration: FIG. 127.--Specimens of Class Lettering and Numbering (Section 339).] The chief points to emphasize in these suggested letterings are that the class letter and number should always occupy the same relative position irrespective of the size of the volume, namely, about two inches from the foot, and that alphabetical classes like Fiction, Poetry and Essays should be boldly lettered with the first three letters of the author’s surname, or numbers from an author table, while _Individual_ Biography only should be similarly marked with the surname letters of the _subject_ of the biography, but not the author, save in the case of autobiographies, letters, etc. If it should be thought necessary to add the accession numbers, they can be placed out of the way in the top half-panel, as shown in No. 7, while shelf colours for open access can be added at the points suggested in Section 243. [Illustration: FIG. 128.--Specimens of Class Lettering and Numbering (Section 340).]