It's been more than two decades since I read anything by Philip José Farmer, the venerable science fiction writer who passed away yesterday. So you'll have to take the following words of praise with a caveat that applies to all the literature I enjoyed in my early teens: I can't promise I'd still like his books if I opened any of them again today.
But in my memory, Farmer was the sophisticate on the science fiction shelf. This wasn't just because he was one of the first scribblers in the sf ghetto to write directly about sex. It reflected the clever literary games he loved to play. Farmer tinkered with characters invented by everyone from Kurt Vonnegut to L. Frank Baum, plus some bona fide historical figures as well. (His Riverwold series threw dead men as varied as Mark Twain, Tom Mix, and Sir Richard Burton into the same setting.) I suppose you could call Farmer an exceptionally talented author of fan fiction. Like the most disreputable fanficcer, he often inserted stand-ins for himself into his stories -- he conveniently gave them his own initials, the better for readers to recognize them as the author -- though unlike the typical Mary Sue, the fictional PJF might turn out to be a villain or a fool.
Thinking back all these years later, two of his short stories stand out in my mind. One was about a mysterious object that appears in the sky and gradually begins to erase everyone's memory. It was written in diary form, as the narrator gradually regresses to childhood. The other was a double pastiche: an attempt to imagine what the Tarzan stories would have been like if they'd been written by William Burroughs instead of Edgar Rice Burroughs. Google reveals that the latter tale is called "The Jungle Rot Kid on the Nod." That title alone should be enough to guarantee Farmer at least a minor literary reputation.