The Library of Congress Classification arranges materials by subjects. The first sections of the call number represent the subject of the book. The letter-and-decimal section of the call number often represents the author's last name. And, as you recall, the last section of a call number is often the date of publication. example:
Because books are classified by subject, you can often find several helpful books on the same shelf, or nearby. For example, within the same call number LB2395, there are other guides for college study.