What if your double from a parallel universe showed up on your doorstep one day? What if said double turned out to be an asshole of epic proportions who shunted you into another universe while he usurped your life?
That's the problem John Rayburn is facing in The Walls of the Universe. His double, John Prime for clarity, tricked him into using his malfunctioning transporter device. Will John be able to fix the wreck Prime has made of his life when or if he can fix the device and make it back home?
The Walls of the Universe was a lot better than I anticipated. Prime and Rayburn contrast in interesting ways. While Prime tries to make money right away by "inventing" the Rubik's Cube in Rayburn's home universe, Rayburn tries to stay out of the way of things in the universe next door while he studies the device... until he accidentally invents pinball.
The villains are invisible for most of the novel and seemed a little tacked on, though the idea of sinister Germans always appeals to me. The supporting cast was fairly well although I can't really see both Johns being so enamored with Casey. Grace was easily my favorite of the supporting cast.
The ending leaves things open for a sequel. It was hinted that John's device isn't related to those of those the enemy use, and the are hints of universe-hopping civilizations that could be used for further stories.
The Walls of the Universe was a fun read and should appeal to fans of dimension jumping, parallel universes, and the like. If you tried Neil Gaimain's Interworld and found it lacking, this might be what you need to soothe your wounds.