Save your time and your money. Gary Jennings is no longer with us (deceased in 1999), but the 2 authors who actually wrote 2012 were woefully inadequate in their attempt in emulating the Gary Jennings work ethic--from the writing style to the supposedly historical research which is the Jennings' bastion is sorely lacking. Granted, the 2012 (insert your own adjective here) is recent in the media spotlight, I believe that more research could have made a more interesting read.
I also take issue with the length of the book (388 pages) when it comes to reading such tomes as Aztec, Spangle and Raptor. The depth of the characters and historical context is once again lacking. I'm not sure if the intention of the writers was to put something out there as quickly as possible without the consideration of what the Jennings legacy and standard has left us. This book just doesn't hold the candle to any of the other Jennings' books.