U.S. Route 99, unofficially the "Pacific Highway", no longer exists. It was replaced by interstate 5 in the 1970s and has been completely decommissioned. But major sections of former U.S. Route 99 are still very much with us in California, Oregon, and Washington.
Following his "U.S. Route 395" and "U.S. Route 95", this is Mike Newlon's third book about U.S. highway adventures in his classic 1969 Porsche 912. 
Ride with Mike, perhaps again, on this trip as he drives the full surviving length of historic former U.S. Route 99, northbound from Mexico to Canada, in April of 2008.