In Christine Schirrmacher's postdoctoral thesis, for the first time one finds reviews of original voices coming from Islamic theology on the topic of religious freedom and apostasy. Arabic, English, French, and Urdu texts have been translated and analyzed and thus made accessible. There are basically three positions which are defended on falling away from the Islamic faith: Complete advocacy of religious freedom, the complete denial of religious freedom with a call for the immediate application of the death penalty for apostates, and the centrist position. The centrist position, however, which allows inner freedom of thought and warns against premature persecution, calls for the death penalty in the case of open apostasy (e.g., in the case of conversion to another faith). Within established Islamic theology, the latter approach is nowadays the most frequent point of view found. These three main positions on apostasy are introduced in this postdoctoral thesis by means of the publications of three influential 20th century theologians: Yusuf al-Qaradawi (b. 1926), Abdullah Saeed (b. 1960), and Abu l-A'la Maududi (1903-1979). They all have followings of many millions of people and have political influence at their disposal. The study explains why in many Muslim majority countries there is still today only very limited or sometimes no freedom of religion (in the sense of the Universal Declaration of Human Rights adopted by the United Nations in 1948) for converts, critical intellectuals, artists and progressive Quranic studies specialists, journalists and secularists, agnostics and confessing atheists, enlightened thinkers, women's rights and human rights activists as well as adherents of non-recognized minorities. Prof. Dr. Christine Schirrmacher (MA in Islamic Studies 1988, Dr. phil. Islamic Studies 1991) studied Arabic, Persian, Turkish, Middle Eastern History and Islamic Studies in Giessen and Bonn, Germany. She is currently Professor of Islamic Studies at the ""Evangelisch-Theologische Faculteit"" (Protestant University) in Leuven/Belgium as well as at the state University of Bonn/Germany, where she teaches at the department of Islamic Studies and Middle Eastern Languages. Additionally she had guest professorships, eg at the State University of Erfurt (chair of Islamic Studies) and at the department of Anthropo-Geography at the State University of Tubingen/Germany. Dr Schirrmacher has given guest lectures on several continents, eg recently at the University of Hongkong, Sofia/Bulgaria and Brest/Belarus and has visited most countries of the Middle East. Schirrmacher is head of the International Institute of Islamic Studies (IIIS) of the World Evangelical Alliance as well as of its German speaking counterpart run by the Evangelical Alliance of Germany, Switzerland and Austria. She is ""Commissioner for Islamic Affairs,"" i. e., the official speaker and advisor on Islam for the World Evangelical Alliance (WEA). Schirrmacher also lectures on Islam and security issues to the German parliament and different government institutions, eg to the Academy of Foreign Affairs Germany, is author of about 15 books on Islam some of which are translated into English, Spanish, Romanian, Korean and Swahili. She is engaged in current dialogue initiatives, like the conference ""Loving God and Neighbour in Word and Deed: Implications for Muslims and Christians"" of the Yale Centre for Faith and Culture, Yale University, New Haven/Connecticut, in July 2008."