Staying up to date with the latest developments in a certain eld 399 495 417 508 of research requires scanning of recent issues of all relevant journals. Due to the quick growth of the scienti c literature this can turn into quite a time consuming task. Thanks to online services like NCBI's Entrez 1 , it has become possible to search huge libraries for speci c articles without leaving the desk. Entrez provides free access to several scienti c databases including PubMed, the world's largest database of biomedical literature. Staying abreast of the current state of science requires frequent electronic library searches because interesting documents can be overlooked if searches are not made regularly. However carrying out searches can be uninteresting and laborious, particularly at times of day when traÆc on the Internet is slow.
PubCrawler is a free alerting service that scans daily updates to the NCBI Medline (PubMed) and GenBank databases using search parameters (keywords, author names, etc.) speci ed by the user. The program keeps track of what records have been seen previously and only shows new hits. The results are presented as an HTML Web page, similar to the results of an NCBI PubMed or Entrez query. PubCrawler is available as a WWW Service or as a stand-alone program.
With PubCrawler Con gurator an additional web tool is provided to help design searches and setting up PubCrawler options. This allows users to check the syntax of their queries, and to get a feel for how many database entries might match each query in the pro le. Because the search pro le can include an unlimited number of queries, and is stored and can be edited at any time using the Con gurator WWW page, users can build more detailed and comprehensive search pro les than they would by occasional use of Entrez.