The Asimov/Foundation connection is the first thing I thought of when I first saw The Mule's handle as well. Nice to see that I'm not the only one. Growing up I was very much on the same reading track as jazzbo, particularly with respect to Pohl & Kornbluth, Niven, and Zelazny. Also Heinlein, Damon Knight, Kuttner & Moore, Sturgeon, Stapledon, Simak, Disch, Silverberg, Robert Sheckley, Gardner Dozois, Philip K. Dick, Leiber, Piper, and some guy named Sterling. I also branched out and kind of left sf behind, but now I read some occasionally. I must admit I felt a surprising twinge of grief when I heard the news of Damon Knight passing away recently. He was about the last of the old guard, other than Arthur C. Clark. Perhaps it was an uncomfortable reminder of the passage of time.