Nuclear weapons, despite their ability to destroy us, also have the potential to unite humankind because they are a collective problem. They also raise important questions about human nature. Could some of us be so consumed by hatred in a time of peace or war to precipitate their use on a scale greater than the bombings of Hiroshima and Nagasaki? Can we live in a world where the specter of nuclear annihilation hangs over our heads indefinitely, or is it that as long as nuclear weapons exist they will be used again and the consequences will be catastrophic for everybody? Is the prospect of a nuclear-free world a realistic goal or a chimera? Is the theory underpinning the continued existence of nuclear weapons, that of nuclear deterrence, itself, based on delusional thinking? Can we trust ourselves not to use them? Why study them?