This book explores religion's role in shaping a state's nuclear policies. It analyses whether religion becomes a motivating or de-motivating factor in the nuclear weapons programs. The fatwa of Ayatollah Khamenei, the Iranian Supreme Leader, against nuclear weapons is an important factor in the recent debate over the possibility of nuclear weaponization in Iran. At the same time, Pakistan's nuclear tests of 1998 were labelled as tests of an 'Islamic bomb'.