For researching the spread of golf in the U.S., I'd also recommend Stuart Bendelow's biography about his Grandfather, "Tom Bendelow, The Johnny Appleseed of Golf" and Chris Clouser's, "Midwest Associate". Both Stuart and Chris have contributed posts on GCA.com in the past. And, "The Scrap Book of Old Tom Morris" is a good one to have, particularly if you want to follow any of Melvyn's posts. Be mindful that when you start buying golf books, it gets to be quite obsessive and expensive.