This document discusses different types of reference tools, including dictionaries, thesauruses, encyclopedias, and atlases. It provides details on the structure and purpose of each tool. Dictionaries are alphabetical and provide definitions, spellings, pronunciations and parts of speech. Thesauruses are also alphabetical and provide synonyms, parts of speech and example sentences. Encyclopedias have many volumes covering different topics with pictures and detailed information. Atlases contain maps and information about places arranged alphabetically.