Searching by subject for monographic information online in the medical literature is a challenging task. The NLM database of choice is CATLINE. Other NLM databases of interest are BIOTHICSLINE, CANCERLIT, HEALTH, POPLINE, and TOXLINE. Ten BRS databases are also discussed. Of these, Books in Print, Bookinfo, and OCLC are explored further. The databases are compared as to number of total records and number and percentage of monographs. Three topics were searched on CROSS to compare hits on BBIP, BOOK, and OCLC. The same searches were run on CATLINE. The parameters of time coverage and language were equalized and the resulting citations were compared and analyzed for duplication and uniqueness. With the input of CATLINE tapes into OCLC, OCLC has become the database of choice for searching by subject for medical monographs.