This was an interesting read. I've been keen to read Ronson's newer work (So You've Been Publicly Shamed and The Psychopath Test), but I had this one on my Kindle already. 
 It was published in 2001 and seems to have been written pre-9/11. Otherwise, I think the focus would have been a lot more on Islamic extremists and less on home-grown American extremists. 
 Each chapter focuses on a different fringe group (including various arms of the KKK, UFO conspiracy theorists, and several groups who are adamant that the Bilderberg Group rules the world). Chapters are a little inconsistent, some more interesting than others. Ronson does a good job telling the story of his subjects and is a very accessible writer - I enjoyed his writing style very much. 
 I have the expectation that his later books will be better, so am keen to read those. I don't know if this is the best intro to his work, but it was interesting with a few "huh, really?" moments that made it worth the read.