Hi folks, another 'no brainer' is to go to www.genealogical.com and search for your surnames. A large percent of their books are indexed on line. You can enter your surname and first name (upper left hand corner) and it'll tell you which books have hits. You can then buy all those books if you won the lottery. Or use worldcat.org to find a library nearby with the book, see if it is in the FHL, or use the Internet to find free lookups. A number of CDs are on line at www.genealogy.com but require a subscription. It might be cheaper to get for a year than to travel all over the world printing out CDs. Many of these older books are free at google books too. Sometimes this includes ones that Eneclan is selling at a hefty price! I searched Cook and got 22,000 plus hits at genealogical.com .What shows up is a lot in New England and the southern colonies. It's not really common in PA at all. I have also seen where it is an anglicization of Koch, a German name, which we do have lots of in PA. There were also some in NJ, apparently (hits in NJ books) and apparently in the Welsh colony. DNA???? Linda Merle