I was suprised by how much stuff there was not related to the 6er. Some of the technical stuff seemed contradictory to other info I've read. I was happy to have it and have read it, but it left me wanting more. Many errors in the first printing that will have to be cleaned up; to the point where is was annoying. I wish it had focused on just the 6. I think with the proper amount of long term research, it could be better. It was a good effort in my opinion, but more could be done. 6.35 out of 10.