... This thesis sets out to determine the usefulness of morphologic analysis in information retrieval systems, particularly for the retrieval of German-language documents. An experimental retrieval system called IRF/1 was developed as a test bed. It is described in this thesis. IRF/1 is used to compare the retrieval effectiveness of different text processing methods for a test collection of about 300 magazine articles. The evaluated methods are: 1. stemming (as a baseline), 2. base form reduction using morphologic analysis, 3. same as (2) but compounds are split into the base forms of their constituents, and 4. same as (3) but the base forms of compounds are kept along with their parts. Using the standard information retrieval measures of recall and precision, the comparison finds morphologic analysis to be generally more effective than stemming. While morphologic base form reduction only provides relatively little improvement over stemming, decomposition of compounds results in a decisive increase in retrieval effectiveness for German. It can be concluded that morphologic analysis with decomposition of compounds is a very promising approach to improving information retrieval for German and should be further investigated.