The Cato podcast interview of Jesse Walker by Caleb Brown opens with a question about Illuminatus, which I take the liberty of transcribing:
Caleb Brown: I guess my introduction into conspiracy theories was Robert Anton Wilson and Robert Shea's The Illuminatus trilogy, which for those who haven't read it, sort of wraps up all of the great conspiracy theories effectively into one grand conspiracy theory --
Jesse Walker: Or a mosaic of conspiracies --
Caleb Brown: That have somehow been going for thousands of years.
Jesse Walker: The great thing about that book, which is in my book -- People sometimes say it treats every conspiracy as true. It might be more accurate to say that it treats every way at looking at the world as equally true and equally absurd, and then sort of sees what it can tease out from that. Those two, particularly Wilson, represent what I call in the book the ironic style of political paranoia, or the ironic style of conspiracism, I should say. That's people who, they're not interested so much in talking about conspiracy theories to debunk them, or to say hey this is one that I think that is true, although sometimes they might do that their own merits, but just to have fun with them, to explore them. They're this big mutant mythology. Let's find what kind of laughs we can find in there. Let's find what kind of social insights can be found in there. [I snip the last part of the answer, which explains how Walker's book does something similar, treating conspiracy theories as folklore.]
Transcribing is a pain, so I hope Jesse forgives me for truncating his answer. The whole podcast is worth listening to (about 15 minutes) and Illuminatus! comes up again. Walker observes, "The authors have said that some of the fun pranks that they pulled, is there are some things that sound like plausible history that could be true, but they just completely made up historical details. There are other things that sounded completely absurd but are actually true that they threw in there."