This project examines anaphora (the linguistic device of abbreviated subsequent reference to a concept) in information retrieval (IR) systems in order to develop procedures to recognize anaphors in text and distinguish between anaphoric and non-anaphoric uses of a given term, estimate the number of anaphors appearing in bibliographic records, and assess the effect on retrieval performance when anaphors are replaced by their referents. In the first phase of the study, rules were developed to form the basis for an automatic procedure to recognize anaphoric terms in bibliographic databases. An examination of the titles and abstracts of 600 documents revealed that only 3.67 true anaphors occurred in the average abstract, suggesting that the effect of treating these terms in some way to improve retrieval performance might be slight. In the second phase, 12 term weighting schemes were used to determine the relevance of each document to the corresponding query, and user's relevance judgements for the same searches were compared with the system's judgements for (1) searches using abstracts in which anaphors had been replaced with their referents, and (2) searches using abstracts with unresolved anaphors. These comparisons yielded mixed results, indicating that a straightforward substitution of referents for their anaphors will not improve retrieval performance in the majority of cases. It is concluded that future studies which treat document length more explicitly and study documents on an individual level are necessary. A bibliography is provided, and five lengthy appendices include the preliminary test and functional indexes, the retrieval experiment and functional indexes, results of the linguistic analysis, test results of rule sets, retrieval test results, and summaries of statistical results for searches of INSPEC and PsycINFO. (KM)