This site is a companion to The Invisible Web: Finding Hidden Internet Resources Search Engines Can't See by Chris Sherman and Gary Price.
It includes a directory of some of the best resources the Invisible Web has to offer. The directory includes resources that are informative, of high quality, and contain worthy information from reliable information providers that are not visible to general-purpose search engines.
We give precedence to resources that are freely available to anyone with Web access. However, we do include a few select resources that are either free to search but have resulting fee-based content (such as News Library), or charge a small fee to search and a fee to access full-records. Some sites may be free to search and access full records, but require the user to register at no charge before granting access.
In general, we like the idea of comparing the resources available on the Invisible Web to a good collection of reference works. The challenge is to be familiar with some key resources prior to needing them. Information professionals have always done this with canonical reference books, and often with traditional, proprietary databases like Dialog and Lexis-Nexis. We encourage you to approach the Invisible Web in the same way—consider each specialized search tool as you would an individual reference resource.