The OAPEN Library contains freely accessible academic books, mainly in the area of Humanities and Social Sciences. OAPEN works with publishers to build a quality controlled collection of Open Access books, and provides services for publishers, libraries and research funders in the areas of dissemination, quality assurance and digital preservation.

OAPEN combines the advantages of an independently operating commercial venture with the benefits of being embedded in the scholarly community. Joining the OAPEN network involves no membership costs, while giving you privileged access to information-sharing and lobbying that are an important part of the initiative. Listing your titles in the OAPEN Library involves a fee which starts at around €700, depending on the size of your frontlist, as well as the number of titles submitted to the OAPEN Library.