The largest book in the world is a photo collection entitled Bhutan: A Visual Odyssey Across the Kingdom. It measures five feet wide by seven feet long, weighs 133 pounds, and is 122 pages long. It was written by MIT scientist Michael Hawley to raise money for education in that very poor nation. Amazon is currently selling it for $30,000.
http://www.amazon.com/gp/product/B00016CAZ6?ie=UTF8&tag=oddee-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=B00016CAZ6 via Oddee