The original Commander Keen game, Marooned on Mars, included, among the items that would add to Keen's score (and thus bring him closer to an extra life), this, the "Book" in the game's documentation, worth 1000 points:
It's not hard to see why this fascinated me from an early age, though in the early 90's I had only a vague notion of who Kant was. I actually e-mailed Tom Hall, creator of Keen, about it, and it's intentional - Keen is supposed to be a boy genius and Kant is a small name suitable for being put on a tiny sprite.
Marooned on Mars was released in 1990. In 1987, this book was published by Hackett:
Coincidence? Or did someone at id happen to have that book?
I'd ask Tom Hall again, but that seems like one of those tiny details you forget the moment after it happens.
Just thought that was interesting.