Kahn educated Kubrick on the concept of the semirealistic "cobalt-thorium G" doomsday machine, and then Kubrick used the concept for the film. Kahn in his writings and talks would often come across as cold and calculating, for example, with his use of the term "megadeaths" and in his willingness to estimate how many human lives the United States could lose and still rebuild economically. Kahn's cold analytical attitude towards millions of deaths is reflected in Turgidson's remark to the president about the outcome of a preemptive nuclear war: "Mr. President, I'm not saying we wouldn't get our hair mussed. But I do say no more than ten to twenty million killed, tops, uh, depending on the breaks." Turgidson has a binder that is labelled "World Targets in Megadeaths", a term coined in 1953 by Kahn and popularized in his 1960 book "On Thermonuclear War".