The Encyclopedia of Marxism is a free, volunteer-based, bottom-up online encyclopedia, created by an International group of discipline experts and grown with the help and support of users. It has a complex hypertextual architecture enabling users to move from a definition/idea to another with semantical and structured associations. An internal search engine, powered by Google, provides also star-rated metainfo to indicate the pertinence and the quality of the retrieved resources. Glossaries, keywords directories and links are also provided and users can navigate among pictures, archives and quotations. Despite its lack of academic or institutional authority, the encyclopedia provides useful and rich data upon a relevant historical and political topic. All contents and concept descriptions are freely accessible and can easily be saved and downloaded. The entire website features a clear and easy interface design and content organization, with no need for specific aids. The encyclopedia’s pages and contents are provided in many different languages and released under a Creative Commons license.