This article assesses concerns about the potential development of new weapons and risks of mass destruction made possible by nanotechnology - the rapidly evolving field of atomic and molecular engineering. It will argue that such concerns are valid and will need to be addressed by the international arms control and non-proliferation regime. The paper concludes with an appeal for such an engagement to begin sooner rather than later. Weapons of mass destruction (WMD) are already banned from outer space under the terms of the 1967 Outer Space Treaty. Before long, there may be need for an 'inner space' treaty to protect the planet from devastation caused - accidentally, or by terrorists, or in open conflict - by artificial atomic and molecular structures capable of destroying environments and life forms from within. 'Nanotechnology and Mass Destruction' in _Disarmament Diplomacy_ | 
