Found my copy of 3D Game Alchemy, a 1996 tome on building levels for classic Doom engine games. It's over 700 pages. There's a lot of information on all fundamental aspects of building Doom levels. It comes with a CD with outdated tools and hundreds of wads that probably suck and a graphics library of 350 Doom-ready images. I wonder if anyone has used these graphics to make anything significant. It's available on the Internet archive: https://archive.org/details/3-d-game-alchemy-for-doom-doom-ii-heretic-and-hexen_202309#doom#DoomMapping