In The Spread of Nuclear Weapons: A Debate Renewed, professors Waltz and Sagan resume their well-known dialogue concerning nuclear proliferation and the threat of nuclear war. Kenneth Waltz, Senior Research Scholar in the Arnold A. Saltzman Institute of War and Peace Studies at Columbia University, expands on his argument that "more may be better," contending that new nuclear states will use their acquired nuclear capabilities to deter threats and preserve peace. Scott Sagan, the leading proponent of organizational theories in international politics, continues to make the counterpoint that "more will be worse": novice nuclear states lack adequate organizational controls over their new weapons, resulting in a higher risk of either deliberate of accidental nuclear war. Treating issues from the ’long peace’ between the United States and Soviet Union made possible by the nuclear balance of the Cold War to more modern topics such as global terrorism, missile defense, and the Indian-Pakistani conflict, The Spread of Nuclear Weapons: A Debate Renewed is an invaluable addition to any international relations course.