Term selection is based on the vocabulary found in documents entering the NCJRS system, on the frequency of term usage in the literature, and on the language of the user community. The 5-digit number assigned to each term is a descriptor code for searching on that term. A scope note explains the specific use of a term in the NCJRS system. Notations appear under a substantive descriptor, when appropriate, in the following order: scope note, (SN), used for (UF), broader term (BT), narrower term (NT), and related term (RT). The thesaurus also includes organizational descriptors and geographic descriptors. In addition, a 'Key-Word-Out-of-Context' (KWOC) list follows the thesaurus proper. Each significant word in each thesaurus term is extracted, listed alphabetically, and followed by a listing of all the terms containing that word. An explanation of how to use the thesaurus notes that terms are alphabetized on a letter-by-letter basis and describes both how to select the most specific descriptor and how to focus a search. (Author abstract modified)