in general, one must keep in mind what is presented is the most pessimistic of weapon effects ranges. As the scaling laws these tables and graphs were derived from assume a simplistic flat terrain with no intervening skyscrapers or other objects that would attenuate the blast and provide shadowing from the thermal effects. When real world city terrain topography is included in these weapon effects calculations the lethal ranges are downgraded considerably. According to the 1946 book Hiroshima, in the days between the Hiroshima and Nagasaki atomic bombs in Japan, one Hiroshima policeman went to Nagasaki to teach police about ducking after the atomic flash. As a result of this timely warning, not a single Nagasaki policeman died in the initial blast. This allowed more surviving Nagasaki police to organize relief efforts than in Hiroshima. Unfortunately, the general population was not warned of the heat/blast danger following an atomic flash because of the bomb's unknown nature. Many people in Hiroshima and Nagasaki died while searching the skies for the source of the brilliant flash. Recent scientific analysis has largely supported the general idea of sheltering indoors in response to a nuclear explosion. Staying indoors can offer protection both from the initial blast as well as the following radioactive fallout that accumulates during the aftermath. Additionally, such a response would leave roads clear for emergency vehicles to access the area. This is termed the shelter in place protocol, and together with emergency evacuation advice, they are the two countermeasures to take when the direct effects of nuclear explosions are no longer life-threatening and the need for protective shielding from coming in contact with nuclear weapon debris/fallout in the aftermath of the explosion, begins to become a concern. Historical context The United States' monopoly on nuclear weapons was broken by the Soviet Union in 1949 when it tested its first nuclear explosive (Joe-1), and with this many in the US government and public perceived that the nation was more vulnerable than it had ever been before. Duck-and-cover exercises quickly became a part of Civil Defense drills that every American citizen, from children to the elderly, practiced to be ready in the event of nuclear war. In 1950, during the first big Civil Defense push of the Cold War and coinciding with the Alert America! initiative to educate Americans on nuclear preparedness; The adult-orientated Survival Under Atomic Attack was published and contains "duck