Prequel to "A Fire in the Deep", but can stand alone. Two human societies, one a free-wheeling trader group, and one an authoritarian imperialist regime, are fighting to control exploration of a once-great alien culture, now degraded. Interesting technologies involved, complex plot, treachery in all directions. It's pretty much a standard space epic - a fun read but not a lot of content. If you like Niven's work, you'll probably enjoy this too.
This is an amazing book. This is a book that reminds you (in case you'd forgotten) why it is that you like science fiction in the first place. Characters that you can identify with, aliens that are completely plausible and seem real, situations that you keep you at the edge of your seat. Wonderful, wonderful, wonderful!
Great book, especially if you like military style sci-fi. The only problem I had with it is that it is not appropriate for children. Too much psychological warfare and one moderately explicit sexual scene. Based on my reading of this book, I will read more Vernor Vinge.