Published in the early 90s, A Fire Upon the Deep is a solid SF story with two strong elements: firstly a unique cosmology which posits different zones of thinking and technological ability possible in distinct geographic areas of the galaxy, and secondly its portrayal of an alien species that forms identity when it reaches a critical mass of individual minds joining together in a pack. Both ideas are ably and entertainingly expounded by Vinge as background to a galaxy-spanning adventure story with high stakes for our heroes. It's good, solid science fictional fun even if the middle section drags a little and the human characterisation seems a bit two-dimensional.