I was flipping through his book and came to the section on making your own games. Several pages were devoted to ZZT. He even had a few screenshots, although they were taken while ZZT was in windowed mode.
In his instructions on starting up ZZT, he said something along the lines of "Press 'W' to get a list of worlds. Your screen should look something like this, especially if you've downloaded my old Yoshi games." Indeed, the screenshot listed several worlds that did not come with ZZT.
I peered closer to see the world names of Kohler's ZZT games. I haven't played any of his games, so I shouldn't have recognized any of the titles. However, two names managed to catch my eye:
It appears that Chris Kohler had been playing a few contemporary ZZT games in addition to looking back at his own work! Of course, this was just a little detail that few people will notice, but hey, our very own MadTom influenced 16 characters in a screenshot in an O'Reilly book. That's still something.BURGLAR1
BURGLAR2
But it gets better. A page or two later, Kohler went on to say how ZZT games quickly began to push ZZT's limits. As an example of contemporary ZZT limit-pushing, he put in a screenshot of this, pointing out the detailed graphics.
It wasn't credited to anyone, but still... it's in a book! That counts for something, right?
Kohler also mentioned z2 and a couple of other sites (I think http://www.chocobo.org/~butz/zzt.htm was one of them), but we're listed with our old the-underdogs URL. Somebody ought to contact him.
P.S. MadTom is famous.