This is pretty great. A 4th dimensional trouble maker screws around with a simple, selfish 3d man, making him addicting to a 4d drug for his own purposes. Classic, rollicking, fun. This one made me realize I have been missing out on a good, active author in Rudy Rucker.
It's nice when you realize that the main character really isn't a very thoughtful or good person - and that's okay, the story just carries you forward and it'll be fine.