2012: The War for Souls by Whitley Strieber is a bit of a trip. As an author, Mr. Strieber is hit and miss. The Hunger was excellent. The sequel not so much. I forget it's name. I didn't finish it. 2012 is an ambitious book but I think it works.
There are three Earths. One in each of three dimensions. One Earth has two moons and never had a World War. One Earth is ruled by a species that evolved from dinosaurs instead of primates. Then there's our Earth. The dinosaurs have been breeding like rabbits. They need to take over the two moon Earth. They tried 13, 000 years ago and failed. The Maya were there and they predicted the next time the two moon Earth would be vulnerable to attack again. In the year 2012. In that year the three Earths would be aligned and travel between them would be possible.
The novel jumps around between the three Earths. Sometimes I had to go back and make sure I understood which Earth I was in. It got really confusing when characters from each Earth started moving between the universes. 2012 is part sci-fi, part horror, part cautionary tale. Think Invasion of the Body Snatchers meets Saw meets An Inconvenient Truth. There's a lot of death and violence. It gets a bit cartoon-like at the end. I found myself skimming over big sections. I got that the dinosaurs were bad early on. I didn't need to keep having evidence pushed in my face. They do some fairly disgusting things. Images that I may not get out of my head for quite a while. I hate that.
If you're a sci-fi/alien/prophecy/disaster fan you'll like this book. It's not the best book I've read in this category but it was interesting enough that I wanted to finish it. I'm also happy about the way things turned out. That's a big plus. I don't like wading through guts and gore to get to an end I think is stupid.