Robert Anton Wilson's work, like that of his favorite composer Ludwig van Beethoven, falls pretty clearly into three periods, and Masks of the Illuminati dates from the middle period, corresponding to Beethoven's second or "heroic" period. I would date RAW's middle period as 1969-1985; 1969 is when he began work on the Illuminatus! trilogy and 1985 is the copyright date for The Widow's Son, Wilson's last great novel.
Masks has a 1981 copyright date. Interestingly, the copyright date for The Earth Will Shake is 1982, suggesting a period in Wilson's career when he concentrated on writing relatively straightforward novels.
I could not find much material on the Internet that sheds light on Wilson's purpose and tactics in writing Masks. In this interview, he explains that it was his attempt to follow an established commercial template: "I can't write a formula book. I tried once, that was Masks of the Illuminati. I started out to write an ordinary detective story, and then my imagination ran away with me and out came Masks Of The Illuminati which is a detective novel but hardly an ordinary one."
Masks originally was published in 1981 as a Timescape Book, an imprint of "Pocket Books, a Simon & Schuster of Gulf and Western Corporation," according to the title page. My Pocket Books copy has 294 pages. It was reprinted by Dell Books as a 355-page book; the text appears to be identical, with the page difference accounted for by the fact that the Dell edition is printed in larger type.
Robert Anton Wilson's Boswell, Eric Wagner, tells me that as far as he knows, there is no difference in the text between the Pocket and Dell editions. Wagner's book, An Insider's Guide to Robert Anton Wilson, includes an eight-page essay, "Joyce's Influence on Masks of the Illuminati."
Dan Clore (proprieter of Robert Anton Wilson Fans on Facebook) says, "RAW was clearly deep into Lovecraft at the time he wrote Masks, not just HPL's own work, but using Supernatural Horror in Literature as a guide to earlier weird fantasy." Dan recommends his own book to learn more.
Wilson's editor for Masks was David G. Hartwell, the prominent science fiction book editor. When Hartwell took over as editor of Timescape, he inherited a number of books purchased by his predecessor. Hartwell had the power to dump any books he didn't like, but he was a Wilson fan and went on to publish the Schroedinger's Cat trilogy, Cosmic Trigger I and Masks of the Illuminati. Alas, he remembers little about Masks, other than "I liked it and I was pleased to publish it at the time."
The online discussion group for Masks of the Illuminati starts Monday. I'll stretch out the discussion a little longer than I originally planned to cover 10 weeks, just to make it easier to have a detailed discussion and to let people keep up (or catch up.) I'll divide the book up into 10 sections, using both the Dell edition and the Pocket Books edition to provide a guideline. Next week, for example, read up to about page 29 in the Pocket Books and up to about page 35 in the Dell. You could read it this weekend, as I will, if you want to be able to post comments Monday.