HathiTrust is currently experimenting with large-scale full text searching as part of an effort to create a mechanism to search across the entire repository. As an initial public beta of full text search functionality, we are offering a simple mechanism to search across all of the fully viewable works (both those in the public domain and those for which we have permissions) and a sprinkling of search-only works (i.e., in-copyright works where we may not show the text of the work).
The size of the content indexed is approximately 500,000 volumes, and the majority of the works are fully viewable. Although this is a fully functioning and reliable search mechanism for these works, we provide it as a public beta in order to learn more about these large search indexes in a public setting.
More information on our process to explore issues in this area is available in the HathiTrust.org large-scale search report.
Please visit http://www.hathitrust.org/ to learn more about the HathiTrust Shared Digital Repository.