Be thoughtful about how you conduct searches. Sometimes, especially when searching in a contained environment like our library catalog, it will be best if you search broadly first (search St. Louis History for example). Browse through the results and see what is there. If your search is too narrow you might get zero results. We do have books on your topic but you will have to search strategically.
For example. If you are looking for information on "St. Louis highways" and that search is made in the catalog, one book comes up. However, if you think what the broader topic might be there are several other sources. Urban renewal, for example, is a relevant topic and if you then searched "St. Louis urban renewal" three more relevant books will come up. The key is to be persistent and to make multiple searches at different points in your research process.