Serious Games, Clark Abt, University Press of America (1970)

I have given the original publication date by Abt Associates in 1970, and published by Viking in 1971, the current edition was first reprinted in 1987.  I have recently become interested in game-based learning.  This seems to be an area in which the basic vocabulary is just becoming standardized.  The title of the book appears to be the first appearance of the terminology "serious games."  Much of the literature in game-based learning can be traced back to this seminal work.  Well worth reading.