Little Wars by H. G. Wells

H.G. Wells wrote a rulebook for toy-soldier combat in 1913 and accidentally founded the wargaming hobby — an irony he would have found grim, given his pacifist intent. Historically significant and full of Wells's characteristic wit, but the rules are verbose and disorganized, and Gary Gygax's acknowledgment tells you who this really speaks to. A fascinating historical document, not a practical book.