DOC GIFFIN rarely teed it up with Arnold Palmer ("I'm a hacker," he says), but for 50 years they were daily playing partners. Separated in age by just 10 months, the two would huddle in Palmer's office, tucked into the property of his Latrobe, Pa., home, to take on the unrelenting busy-ness of being the King: the VIP outings, global travel, myriad press requests, and on and on. In 1966, Palmer asked Doc, then press secretary of the PGA Tour, to be his right hand—and, on occasion, his voice, as the ghostwriter of so much of the ink we thought of as "By Arnold Palmer." Barely a week after his boss's passing, the doctor, now 88, is still keeping office hours. Palmer's absence in Latrobe is, as you'd imagine, profound.…