Although we are unable to discuss all of the functionality available in PepTool and GeneTool, it should be evident from this brief review that both packages offer a great deal in terms of functionality and ease-of-use. Furthermore, a number of useful innovations including platform-independent GUI design, networked parallelism, direct internet connectivity, database compression, and a variety of enhanced or improved algorithms should make these two programs particularly useful in the rapidly changing world of biological sequence analysis. More complete descriptions of the programs, algorithms and operation of PepTool and GeneTool are available on the BioTools web site (www.biotools.com), in the associated program user manuals and in the on-line Help pages.