O.D. (Olaf) Janssen (Dongen, 1973) studied astronomy in Leiden and has been active in the library and heritage field since 2001. He is co-founder of The European Library and a pioneer at Europeana, the European Union cultural heritage platform. He is currently working on Open Data & Wikimedia-coordination at the National Library of the Netherlands (KB) in The Hague. He stimulates and facilitates activities that open collections, knowledge, data and bring the staff at the KB and the projects of the Wikimedia movement, such as Wikipedia, together. He is also active in the movement as a volunteer.