It has been generally accepted that Germany and Japan were years behind the Allies in producing a nuclear weapon during World War II and that Japan in particular was technically incapable of doing so. The author argues that these assumptions are unfounded and reveals that an Axis nuclear weapon was a very real threat to the Allies. Philip Henshall begins by outlining how Germany's conventional military situation began to deteriorate from 1943 onwards, how interest was revived in secret long-range weapons, and how SS General Kammler assumed virtually complete control of all long-range weapons projects. The origin of weapons in Germany is examined, with parallel references to the USA's "Manhattan" Project and, Henshall puts forward his theory that the leading figure in German nuclear science, Heisenberg, knew what was required to build an atomic bomb and fully understood the physics of the device - contrary to the accepted version of events.