1994. The book is set in 1960 and describes "the engines of war", which have become so efficient that war is inconceivable and all countries are at a perpetual stalemate. MAD has been invoked by more than one weapons inventor. For example, Richard Jordan Gatling patented his namesake Gatling gun in 1862 with the partial intention of illustrating the futility of war. Likewise, after his 1867 invention of dynamite, Alfred Nobel stated that "the day when two army corps can annihilate each other in one second, all civilized nations, it is to be hoped, will recoil from war and discharge their troops." In 1937, Nikola Tesla published The Art of Projecting Concentrated Non-dispersive Energy through the Natural Media, a treatise concerning charged particle beam weapons. Tesla described his device as a "superweapon that would put an end to all war." The March 1940 Frisch–Peierls memorandum, the earliest technical exposition of a practical nuclear weapon, anticipated deterrence as the principal means of combating an enemy with nuclear weapons. Early Cold War In August 1945, the United States became the first nuclear power after the nuclear attacks on Hiroshima and Nagasaki. Four years later, on August 29, 1949, the Soviet Union detonated its own nuclear device. At the time, both sides lacked the means to effectively use nuclear devices against each other. However, with the development of aircraft like the American Convair B-36 and the Soviet Tupolev Tu-95, both sides were gaining a greater ability to deliver nuclear weapons into the interior of the opposing country. The official policy of the United States became one of "Instant Retaliation", as coined by Secretary of State John Foster Dulles, which called for massive atomic attack against the Soviet Union if they were to invade Europe, regardless of whether it was a conventional or a nuclear attack. By the time of the 1962 Cuban Missile Crisis, both the United States and the Soviet Union had developed the capability of launching a nuclear-tipped missile from a submerged submarine, which completed the "third leg" of the nuclear triad weapons strategy necessary to fully implement the MAD doctrine. Having a three-branched nuclear capability eliminated the possibility that an enemy could destroy all of a nation's nuclear forces in a first-strike attack; this, in turn, ensured the credible threat of a devastating retaliatory strike against the aggressor, increasing a nation's nuclear deterrence. Campbell Craig and Sergey Radchenko argue that