What is the theme in The Missionary Position: Mother Teresa in Theory and Practice by Christopher Hitchens?

Perhaps foremost among the many books in world literature questioning the value of organized religion are ones of philosophy and history. In general, philosophers critical of religion argue against its ability to satisfactorily answer the eternal questions about why we are here and how to live a moral life. Historians who criticize religion usually point to wars and other forms of degradation or repression that are perpetrated in the name of various religious creeds.