Dialog was one of the predecessors of the World Wide Web as a provider of information, though not in form. The earliest form of the Dialog system was completed in 1966 under the direction of Roger K. Summit. According to its literature, it was "the world's first online information retrieval system to be used globally with materially significant databases". In the 1980s, a low-priced dial-up version of a subset of Dialog was marketed to individual users as Knowledge Index. This subset included INSPEC, MathSciNet, over 200 other bibliographic and reference databases, as well as third-party retrieval vendors who would go to physical libraries to copy materials for a fee and send it to the service subscriber.