Robert Anton Wilson wrote that he and Robert Shea never thought of ILLUMINATUS! as science fiction. Yet, it's interesting to note that every one of his novels were published as part of some publisher or another's science fiction line, and produced by editors in the science fiction world.
ILLUMINATUS! was published as part of Dell's science fiction line and edited by science fiction editors such as David Harris. Jim Frenkel, a well-known science fiction editor, worked to keep the books in print. (More about that soon.)
The three books in the SCHROEDINGER'S CAT trilogy were published as science fiction by Pocket Books. The editor was David Hartwell, a well-known science fiction editor. I am re-reading the cat trilogy now, and I do notice that Wilson referred to it as a "science fiction comedy" and refers to himself as a science fiction writer. MASKS OF THE ILLUMINATI also was published as Pocket science fiction. It's been years since I read it, but at the time, it did not strike me as a science fiction novel.
Even the "historical Illuminatus" books were put out by science fiction publishers. Frenkel was the editor of THE WIDOW'S SON, and the copyeditor was Teresa Nielsen Hayden, a prominent science fiction copyeditor (and a well-known science fiction fan.)
Whatever one thinks of the science fiction genre in general, it is undeniable that science fiction provided RAW with a literary home. It's interesting to compare his career with that of his friend Philip K. Dick, who for many years could only get his novels published because science fiction publishers were willing to publish them.
Can anyone tell me how Wilson reacted, in his later years, when the "science fiction writer" label was put upon him?