Fabric of the Cosmos by Brian Greene

Offers a great explanation of cutting-edge cosmology for non-physicists. Greene goes through the history of cosmology and quantum physics as background for his explanation of string-theory/M-theory, 10-dimensional space, etc. Excellent use of analogies and unexpectedly sprinkled with humor and fun pop-culture references. I already have his other book (The Elegant Universe) in my pile of books to read.