Adnan Oktar (born Ankara, February 2, 1956)--also known by his pen name, Harun Yahya--is a prominent advocate of Islamic creationism in the creation-evolution debate and, more particularly, supports Old Earth creationism. He is against Zionism and Freemasonry and sees them as very interrelated movements, though he denounces anti-Semitism and terrorism, which he says are products of Darwinism. Oktar had defended his views by litigation; he is responsible for the blocking of numerous, high-profile Web sites in Turkey.

Oktar runs two organizations: The Milli Değerleri Koruma Vakfı (Foundation to Protect National Values), which focuses on "moral issues", and the Science Research Foundation (Bilim Araştırma Vakfı, or BAV), which promotes creationism. Oktar founded the Science Research Foundation "to ...peace, tranquility and love", though some media describe the BAV as "a secretive Islamic sect" and a "cult-like organization, that jealously guards the secrets of its considerable wealth". In 2008, Oktar was sentenced by a Turkish court to three years in prison for "creating an illegal organization for personal gain"."