Under the pen-name Harun Yahya, Adnan Oktar is an influential Turkish spiritual leader, author and opinion shaper who has written over 300 books in 73 languages on political, faith-related and scientific issues, which have been read by millions of people, exerting considerable influence on both Muslims and non-Muslims all over the world. More than 20 million people from 167 different countries visit Harun Yahya websites every month.