> At one point I think Vinge showed his manuscript to somebody else, because after that he spends a bit of time defending his description of some of the aliens The author protests a bit too much. Because it's a prequel, there is just a bit too much detail.

Almost surely. He had a number of consultants and others go through _A Fire Upon the Deep_ (which I liked better), as one can see from the annotated edition: http://news.slashdot.org/story/03/09/18/0411259/Review-A-Fir...