What is the best travel guide book to buy for Route 66?

This is a gift for a friend

Please look travel guide book Route 66 at Amazon.

http://www.amazon.com/s/qid=1220722593/ref=sr_st?keywords=travel+guide+route+66&rs=1000&p age=1&rh=i:stripbooks,k:travel+guide+route+66&sort =relevanceT1rank&tag=best-buy-prices-20

Hope this help.

Good Luck.