If you don't take it too seriously, it's a big chunk of fun. The story begins life in a pocket universe on very much a "sword and sorcery" level, but quickly expands its reach into multiple universes, massive artificial intelligences, and a sizable battle for control of the known universe. Plenty of twists and turns along the way and some real tension via the employment of biological weapons. As one other reviewer noted, the concept of "Implied Spaces" is introduced and then fades from view, which is too bad; it's an interesting thought.That said, this book visits a lot of different worlds, and while I found that intriguing, the ending felt like a bit of a dropped ball. Still, interesting characters and places left me giving it four stars. Not Walter Jon Williams' best, but a credible, fun, thought-provoking book.