Project Gutenberg (PG) is a volunteer effort to digitize and archive cultural works, to "encourage the creation and distribution of eBooks." It was founded in 1971 by Michael S. Hart and is the oldest digital library. Most of the items in its collection are the full texts of public domain books. These items are free and can be read online or downloaded. The project is named after Johannes Gutenberg, the fifteenth century German printer who propelled the moving type printing press revolution.