He also wrote a lot about the early days of science fiction in his 1978 memoir, The Way the Future Was. I was particularly fascinated by his association with the Futurians, a NY-based science fiction club which included Isaac Asimov, James Blish, and Cyril Kornbluth.
http://www.thewaythefutureblogs.com/
There are many 'back in the day' stories archived there. It's bothering me quite a bit that his latest "To be continued" won't.