"A Fire Upon the Deep" is about the struggle of men and other species to fight off a god-like presence with some bad intentions for the future of the known galaxy.

This was an overall amazing book. The alien species were very diverse and unlike what you read in other books or see in most movies. The "zones of thought" are a great idea which results in interesting problems and solutions (something that is missing from the second book in the series, "a Deepness in the Sky").

It's a fairly lengthy book, but the last third of the book is extremely thrilling and flies by very rapidly.

This is a must read for every one even remotely interested science fiction or space opera.