Joe,
However, for Joe and Double Camp Followers I found out that the excellent "Double and Mulitple Stars," by James Mullaney, is available on Kindle for a free trial period. (not to be confused with a sample few chapters); Some great chapters on viewing, equipment and anecdotes, measuring techniques, the great double hunters, plus two large and detailed sections on the best doubles. No commitment to buy.
Is this Double Star Festival never to end? Let's hope not! Eugene