Yes, good tennis writings can be hard to find these days. Some of the best on those early years are by A. Wallis Myers, easily the most famous authority of his time. (I think it's a crime he isn't in the hall of fame, BTW.) I have a book by him called The Complete Lawn Tennis Player that is excellent - Nabokov also had it and refers to it in his autobiography, as well as in The Annotated Lolita. A more recent book with some good coverage is Sporting Gentlemen by E. Digby Baltzell, though the author makes a somewhat offensive sociological argument that relates the superiority of amateur tennis to professional tennis and the supposed superiority of the aristocratic classes. One of my very favorite books, and the one that taught me the most about the game when I first read it long ago, is Tennis Styles and Stylists by Paul Metzler, which is easy to read (very informal in tone) and packed with details going back to the very first Wimbledon. There is a wonderful biography of Norman Brookes written by his wife, which has helped me appreciate what a truly great champion he was - certainly one of the greatest of all time, I think. And though you may have trouble finding it, I have the book written by the Doherty brothers, which includes instructional material as well as descriptions of the games of many of their contemporaries. Finally, one fun thing to do is to read the biographies at the Hall of Fame website, and the excellent essays at histoiredutennis.com (though many of the latter are not translated into English).