W Fine arts, plastic and graphic. 
We Landscape gardening. 
Wf Architecture. 
Wj Sculpture. 
Wk Casting, Baking, Firing. 
Wm Drawing. 
Wp Painting. 
Wq Engraving. 
Wr Photography. 
Ws Decorative arts, including Costume.

X-Yf Communicative arts (by language). 
X Philology. 
X Inscriptions. 
X Language. 
Y Literature. 
Yf English Fiction.

Z Book arts (making and use of books). 
Za-Zk Production. 
Za Authorship. 
Zb Rhetoric. 
Zd Writing. 
Zh Printing. 
Zk Binding. 
Zl Distribution (Publishing and Bookselling). 
Zp Storage and Use (Libraries). 
Zt Description (Zt Bibliography; Zx Selection of reading;
                Zy Literary history; Zz National bibliography.)

CHAPTER XXIII

Author-numbers, or book-marks

The books in a given group or class should stand on the shelves in the alphabetical order of their authors’ names, though this is not necessary in a small library.  This result is best secured by adding to the class-mark of every book another mark, called an author-number or book-number or book-mark, made up of the first letter of the author’s name and certain figures.  Books bearing these author-numbers, if arranged first alphabetically by the letters, and then in the numerical order of the numbers following the letters, will always stand in the alphabetical order of the authors’ names.  Different books by the same author are distinguished from one another by adding other figures to the author-number, or by adding to the author-numbers the first letter of the title of each book.

These book-marks cannot be chosen arbitrarily.  They should be taken from the printed set of them worked out by Mr Cutter, and called the Cutter author-tables. (See Library Bureau catalog.)

In a very small library the books in a given class can be distinguished one from another by writing after the class-number of each book the number of that book in its class.  If the class-mark of religion, for example, is 20, the books successively placed in that class will bear the numbers 20.1, 20.2, 20.3, etc.

Fiction should have author-numbers only.  The absence of a class-number will sufficiently distinguish it from other classes.

CHAPTER XXIV

The shelf-list