OAIster is a union catalog of millions of records that represent open access digital resources. OAIster includes more than 50 million records that represent digital resources from more than 2,000 contributors. The records of the open access digital resources available via OAIster lead to a wide range of materials and include: digitized books, journal articles, newspapers, manuscripts, audio files, video files, photographic images, data sets, theses and research papers.