I first became interested in Thomas Barnett's book, "The Pentagon's New Map", after reading about his presentation at PopTech (which you can hear on IT Conversations). I was surprised at the reception that Barnett appeared to be getting from the PopTech audience, and I've been continued to be surprised at the reception his work is getting at places like Worldchanging. So I did what I usually do, which was to put a copy on hold at the library. In the meantime, I started reading Barnett's blog, which has caught me up to speed on many of his ideas (indeed there were few surprises left in the book after a few months of reading the blog).

I'm not going to even try to recapitulate the key arguments in his book. You can read his pair of Esquire articles, his blog, or his book to get the story straight from the source. The book gives you more biographical information on Barnett, the trajectory of his life and how it intersected his ideas. It was also useful to get an insider's view about how ideas succeed or fail in the defense establishment.
I find his Core/Gap theory to be a good explanation of the world that we now live in, along with the probable impact on our national security policy and actions.

There's just one point that I'm having trouble with. One of the key themes of the book is the notion of "A Future Worth Creating". Mostly this refers to the idea that the Core should work to shrink the Gap. And of course, this is where the use of force comes in. The part I'm having trouble with is that I don't think that everyone in the U.S. (much less everyone in the Core, let alone the Gap) will agree that the future Barnett has outlined is the "Future Worth Creating".