1. A method of downloading Hidden Web pages comprising: a) selecting a query term; b) issuing a query to a site-specific search interface containing Hidden Web pages; c) acquiring a results index; d) downloading the Hidden Web pages from the results index; e) identifying a plurality of potential query terms from the downloaded Hidden Web pages; f) estimating the efficiency of each potential query term; g) selecting a next query term from the plurality of potential query terms, wherein the next selected query term has the greatest efficiency; and h) issuing a next query to the site-specific search interface using the next query term.