A few choice excerpts from the letter (which you can view in full at Schoenherr's blog):
'Cosmic Kill' retained all the flavor and action of 'Empire of Evil,' another adventure classic.
I don't understand why you aren't going to use more serials. Surely a month isn't too long to wait, if the story is worth waiting for. It seemed to me that your recent continued tales weren't really long enough to warrant serialization...
By all means keep the book reviews! I don't read them for advice on which books to buy -- I have them before they are reviewed, but I just simply get a kick out of finding someone else's opinion on a book I've read.
I can't understand how a fine writer like Randy Garrett can produce work like he does, then turn around and come up with that 'Kyvor' nonsense. Just a satire on Edgar Rice Burroughs, and not even a good satire."
Even at that age, Ebert was a critic (get it together, Randy Garrett!). The most interesting item is the middle one, when Ebert encourages the publication of book reviews for books he's already read. Ebert was already more interested in criticism as a conversation starter, rather than a passage of judgement. That's fascinating.
Ebert had written on several occasions about not only his love of science fiction itself, but for the conversation those sci-fi stories started. In an essay for Asimov's Science Fiction, he described the influence "prozines" (professional sci-fi magazines) and "fanzines" (the homemade mags that sprung up in their wake) had on his life:
"It was in the virtual world of science fiction fandom that I started to learn to be a writer and a critic. Virtual, because for a long time I never met any other fans; they lived only in the pages of mimeographed fanzines that arrived at 410 E. Washington St. and were quickly hidden among the hundreds of SF mags in the basement, on metal shelves that cost four books of Green Stamps. 'Hidden,' because at first I concealed my interest in fandom from my parents. Fanzines were not offensive in any way -- certainly not in a sexual way, which would have been the worst way of all in a family living in the American Catholicism of the 1950s, but I sensed somehow that they were... dangerous. Dangerous, because untamed, unofficial, unlicensed. It was the time of beatniks and 'On the Road,' which I also read, and no one who did not grow up in the fifties will be quite able to understand how subversive fandom seemed...
For a while, Ebert published his own fanzine, called Stymie. God, I would love to read a copy of that.
Fan friendships, for me, were mostly long distance and conducted by mail, and the influence of fandom was on my writing voice. I became critical. I wrote smart-ass locs about other people’s writing, and read them about my own. I was in a world that stood outside the mainstream. Science fiction was the occasion for fandom, and often the topic, but the subterranean subject was a kind of kibitzing outsider world view. Because of fandom, we got to 1967 ten years before most of the non-fan world."