I was thinking the same thing. The author references the Michael Abrash book, and said it was from "the late 90s." But IIRC, Abrash was writing about BSP in D

I was thinking the same thing. The author references the Michael Abrash book, and said it was from "the late 90s." But IIRC, Abrash was writing about BSP in Doctor Dobbs Journal in the early 90s. IE: Abrash inspired Carmack, not the other way around. In 1992 I was really keen on learning to make arcade style games on the PC, and I studied those Abrash articles like crazy.