For some great context around this, I highly recommend "Playing at the world" by Jon Peterson (<a href="https://www.amazon.com/Playing-at-World-Jon-Peterson/dp/0615642047" rel="nofollow">https://www.amazon.com/Playing-at-World-Jon-Peterson/dp/0615...</a>). It's a fairly detailed history of paper and pencil games with quite a bit of focus on Little Wars, Kreigspiel, and D&D. If you're a gamer, I highly recommend it.