ich can only be learned by doing.
Give fiction no class number, but an author number or "book-mark"
only, as explained in a later chapter. Give all biography a single
letter as its class number, and follow this by the author number.

Distinguish all juvenile books, whether fiction or other, by writing
before their numbers some distinguishing symbol.

Take up first, in classification proper, the subjects of history and
travel, which will be found comparatively easy.

It is easier to classify 25 or 50 books at a time in any given class
than it is to classify them singly as you come to them in the midst
of books of other classes. Consequently, group your books roughly into
classes before you begin work on them.

As soon as a book is classified enter it at once in your
shelf-list--explained in a later chapter--and see that an author-card
for it is put in the author catalog--explained later--with its proper
number thereon.

If, after you have made up your mind, from an examination of the
title-page, or table of contents, or a few pages here and there, what
subject a book treats of in the main, you are still in doubt in what
class to place it, consider what kind of readers will be likely to ask
for it, and in what class they will be likely to look for it, and put
it into that class. In doubtful cases the catalogs of other libraries
are often good guides.

Keep your classification as consistent as possible. Before putting a
book, about which there is any opportunity for choice, in the class
you have selected for it, examine your shelf-list and see that the
books already there are of like nature with it.

Classify as well as you can, and don't worry if you find you have made
errors. There are always errors. Don't get into the habit of changing.
Be consistent in classifying, and stick by what you have done.

CHAPTER XXI

The Dewey or Decimal system of classification

[From the Introduction to the Decimal classification and Relative
index. Published by the Library Bureau, $5.]

The field of knowledge is divided into nine main classes, and these
are numbered by the digits 1 to 9. Cyclopedias, periodicals, etc.,
so general in character as to belong to no one of these classes,
are marked nought, and form a tenth class. Each class is similarly
separated into nine divisions, general works belonging to no division
having nought in place of the division number. Divisions are similarly
divided into nine sections, an