In 1998, the society was developed into the Biohistoricum, a biology museum with a research archive that is considered the only institution of its kind in Germany.
[1] In 2008, Geus published a collection of essays critical of Islam entitled Gegen die feige Neutralität ("Against coward neutrality") with contributions by a number of German academics and journalists, including Karl Doehring, Ralph Giordano, Michael Miersch and Tilman Nagel.
[5] In 2011, Geus published his work Die Krankheit des Propheten ("The sickness of the prophet") which he said examined the pathography of Muhammad, the founder of Islam, from a medical point of view.
[6][7] The book ranked in the top ten non-fiction list of the Süddeutsche Zeitung and Norddeutscher Rundfunk in June 2011, receiving a number of reviews from colleagues and in the press.
In September 2012, the anti-Islam organisation Citizens' Movement Pax Europa had brought the case, which it said was an attempt at "silencing" critical scholars, to an OSCE human rights conference at Warsaw.