I have been reading Winner Take All Politics which I would recommend with the warning that it is a heavy read. I find this a core and growing political problem (note recent interest in the billionaire backers in Wisconsin).
As I have begun to try to process this concern I seem to see other related content. Here is a visual representation of the growing disproportionate flow of wealth within the U.S. economy. The book is partly about this trend and the connection to political decisions.