A recent blog post discussed Michael Johnson's thesis that RAW's writing breaks down into three distinct periods. Wrote Michael, "The middle period writings of RAW (which I consider as 1975-1985, with 1959-1974 the first period and 1986-2005 the third and last, not that anyone had asked) contains an abundance of non-Euclidean political writing, by which he meant that he saw value in left-libertarian and traditionally anarchist thought, and individualist-"right" libertarian ideas."
I endorsed the thesis, noting that I had noticed a similar division. I also suggested that the RAW writings that he'll be remembered for were created almost entirely in the middle period.
Eric Wagner, author of the essential An Insider's Guide to Robert Anton Wilson, posted a long dissent in the comments, and I want to reproduce it here and give Eric "equal time" (but see the discussion in the comments in the original post):
I guess I distrust a three fold division. I think of Carl Dahlhaus's criticism of the three fold division of Beethoven's work, pointing out the continuum of evolution evident, especially in the works on the borders of the traditional three phase division. I think the three fold division works better for Beethoven's work than for Bob's.
With Bob's writing, his sixties work shows his highly developed third circuit with emerging right brain intelligence. This becomes more pronounced in Bob's early 70's writing. In 1973 and 74 Bob had some intense experiences, and his developing writing demonstrates this, especially in the rewrite of Illuminatus! and in Cosmic Trigger.
The end of Cosmic Trigger and Schroedinger's Cat has show him processing the greatest tragedy of his life. This period culminates in the mastery displayed in Prometheus Rising.
I think Bob's writing takes another quantum leap with The Widow's Son, Natural Law and The New Inquisition, all of which show the growing influence of Swift and of living in Ireland, as well as his growing intelligence.
He moved back to the US in the late 80's and metaprogrammed himself for success in Hollywood. He didn't find material success, but his intelligence continued to increase and I think his writing improved. E-Prime became an important tool for him.
I think he became even more interesting and funnier in his final years, especially in the conclusion of TSOG and his Thoughts of the Month on rawilson.com, etc.