There are also Reference Books which are limited to particular subject areas or disciplines. For this reason, it may be helpful to consult the more general tools first. Following are major types of Reference Books you will encounter in libraries. Most of the encyclopedias we are familiar with are general encyclopedias. New Encyclopaedia Britannica .
Subject encyclopedias are limited to particular subject areas or disciplines.
Because they focus only on particular subjects, they often contain longer, more in-depth articles than the general encyclopedias. Encyclopedia of Special Education . Your topic may be covered in more than one article in the encyclopedia. Using the index will insure that you do not miss any relevant articles. The index is usually located in the last volume of the encyclopedia or in the back of a one-volume encyclopedia.