Postcoordination, in which terms are combined at the searching stage rather than at the time of indexing, has been the main form of database access since the 1950s. Reasons for the failure of postcoordinate searches include the absence of specified relationships between terms, the complexity of formulating Boolean searches, and the high frequency of terms in large databases. Recent writers on indexing electronic text have called for precoordination to enhance the precision of retrieval. Among precoordinate indexing structures, a book index with coined modifications is the most precise. The time and cost associated with such customized analysis will, however, limit its application in the electronic environment.