Parallel Worlds : A Journey Through Creation, Higher Dimensions, and the Future of the Cosmos by Michio Kaku--Kaku has, IMO, an astonishing ability to make quantum theory accessible to the average person. I just tend to recommend his books in general, but I found this one particularly fascinating on the subject.
I got Parallel Worlds
by Michio and Fabric of the Cosmos
by Brian, for christmas last year and I haven't found the time to read either. I recieved Hyperspace
for christmas the year before and really enjoyed it. I love Michio Kakus views of theoretical physics and cosmology. I highly recommend any of Michio's books.