David Weigel has an awesome rundown of the 156 book reviews New Gingrich posted on Amazon from 2000 to 2008:
The Gingrich who reviewed 156 books on Amazon was neither the fire starter who led the GOP’s 1994 revolution nor the guy who told National Review that President Obama can only be understood through the prism of “Kenyan anti-colonial thinking.” He was a smart nerd with a lot of time on his hands. If you read his entire collected Amazonian oeuvre, you can watch as an easily entertained quantum physics junkie slowly realizes that he needs to get back into politics and set the rest of us straight-one last time.
There are plenty of thriller reviews in the Gingrich archives, and a few big pop science books about string theory and the Internet. These reviews are more revealing than the policy wonk stuff, which isn’t surprising. We’re talking about the politician who, in To Renew America, mentioned the influence of Toynbee’s A Study of History in the same paragraph as Isaac Asimov’s Foundation novels. Thrills and speculative fiction can, to use a favorite Gingrich phrase, “stretch the mind.” It might not make sense when you hear Gingrich warning of the danger of electro-magnetic pulse attacks or making analogies between World War II and multiple current conflicts. It makes more sense when you see what fiction he reads.
By the time he wrapped up his reviewing career, Gingrich seemed frustrated. The long-term strategic threats of radical Islam or loose nukes should have been so obvious. The worst-case scenarios had been spelled out by countless novelists many times. By 2007, when he launched American Solutions, he could be confident that no one else in politics knew what he knew; no one else had spent so much time in exile.