Open access publications are publicly available worldwide—without legal, technical, or financial barriers and without embargoes that restrict subsequent use by third parties. They have many advantages:

• Higher visibility and citation rate: open-access books are accessed more frequently than closed-access books.
• Ease of discovery: books available in open access can be found through the Directory of Open Access Books (DOAB). They are also visible in bibliographic databases such as BASE, certain subject databases, and discovery services.
• Permanent discoverability through persistent identifiers, preferably a DOI. Other possible identifiers are URN, EPIC, ARK, or Handle.
• Often faster publication times
• Ability to combine research data and multimedia content (enhanced publication).

Note that most research funders expect research results from the projects they fund to be published open access.