Favorite documentation (including manual, hint books)?

I remember as a kid that the engraved travel guide from Quest for Glory 3 to me was just wild. It has art sketches, gives backstory to the land, AND is distinct from the regular manual.

Likewise, Larry 3's part copy protection, part world building primer, Nontoonyt Tonite, is just lovely. Tons of Al Lowe jokes and writing exclusive to it, it's just great.

Never had any of the hint books myself, but I would assume that they also come with some nice stuff.

So, what is everyone's favorite?