Clark C. Abt, an engineer,  was an early pioneer of computer simulations; he simulated air battles, space missions, disarmament inspection systems, and antiballistic-missile defense systems in the 1950s and early 1960s.  His work proved to him that “no satisfactory defense [against these weapons] was feasible” (Abt, 1970, p. xiv).  Abt returned to education to study social sciences, studying with Kissinger at Harvard and Pool at M.I.T.  His doctoral dissertation was “an attempt to identify effective means of terminating wars” (Abt, 1970, p. xiv).  In his book, Serious Games (1970), Abt discusses Nietzche’s distrust of “physically disactive thought” (Abt, 1970, p. 4), and is concerned with the separation of thoughts and physicality, and “mentally inactive action” (Abt, 1970, p. 4), referring to the separation of thought and action as a disease of civilization.  Abt’s view was that games with social decision-making content allow learners to not just think, but participate; thought and action can be integrated.  Serious games “have an explicit and carefully thought-out educational purpose and are not intended to be played primarily for amusement.  This does not mean that serious games are not, or should not be, entertaining” (Abt, 1970, p.9).