"The thesaurus delineates the standard terminology used to index and retrieve instructional materials for exceptional children in the Special Education Instructional Materials Center/Regional Media Centers Network. The thesaurus is presented in three formats: an alphabetical listing (word by word rather than letter by letter), a rotated index, and a listing by category. The alphabetical listing of descriptors provides definitions for all terms, and scope notes which indicate the scope or boundaries of the descriptor for selected terms. Numerous cross references are provided. In the rotated index format, all key words excluding prepositions and articles from single and multiword format, each descriptor has been placed in one or more of 19 categorical groupings."