Getting access to suitable data on a large scale to use as an experimental test bed is also problematic. Although there are now more possibilities with the growth of public domain information on the Internet, there remain severe technical constraints for downloading this material. The project was further constrained by the requirement for databases with an associated thesaurus. Library catalogue systems have been useful for our experiments in the past, but in this instance library records proved too limiting in their subject content to explore fully the potential of interactive query expansion. Although the LBS records were indexed with thesaurus terms, the thesaurus structure and terminology was very limited in comparison with that for INSPEC. Library catalogues are now only one type of information system amidst a great variety of other electronic data. They are probably no longer the most commonly used, nor do they contribute the most representative material for investigating end-user information seeking.