James T. Kirk/Relationships/Friendships/Leonard McCoy

Doctor Leonard McCoy became chief medical officer of the Enterprise after the departure of Dr. Mark Piper in 2265. Kirk formed an easy rapport with his new doctor, giving him the moniker "Bones" (as in the old-fashioned colloquialism "sawbones" for a doctor or a surgeon). Even after McCoy began a program of exhaustive (and exhausting) quarterly physicals and interfered with Kirk's usual diet, their friendship grew rapidly. McCoy was probably Kirk's closest friend, aside, of course, from Spock. ()
The demands of Kirk's career required his best possible health, which Dr. McCoy closely oversaw. Kirk sparred with his crew in the Enterprise gymnasium for exercise. Quarterly physical checks tested his physical fitness as well as general health. In spite of his evident strength and conditioning, Kirk did tend to put on extra weight from time to time. Whenever Dr. McCoy noticed such a gain, he was unafraid to adjust Kirk's diet card, at least once annoying his captain with a plate of dietary salad. ()
Kirk could count on McCoy to express exactly what he thought, whenever he thought it, frequently without the courtesy of a question, and the doctor was often the sharpest observer of Kirk's actions and character. An early act of constructive insubordination occurred when the Enterprise faced the ominous spacecraft Fesarius and Kirk seemed to be pushing young Lieutenant Dave Bailey past his breaking point. McCoy let his opinion loose from beside the captain's chair, and Kirk barked an angry reply--but this led Kirk to realize that poker, not chess as Spock had postulated, was the game he and Commander Balok were really playing. Unintimidated by that angered reply to his unrestrained expression of opinion, McCoy continued that behavior throughout their service together, earning a wide latitude with Kirk. ()
The first time McCoy saved Kirk's life, however, was not in surgery, but instead when McCoy fired a phaser (which itself was unusual for McCoy) in 2266. When the M-113 creature of planet M-113 attacked Kirk, it appeared to McCoy as Nancy Crater, a past love and a particularly powerful impediment to inflict harm. With Spock's help, McCoy was able to see past the creature's camouflage, killing it before it killed Kirk. ()
During the original five-year mission, Kirk recorded a tape of last orders Commander Spock and Chief Medical Officer McCoy were to play upon his death. He urged Spock and McCoy to give each other the same trust and loyalty they had each shown him. ()
McCoy's retirement from Starfleet in 2270 ended abruptly when Kirk, through Admiral Nogura, reactivated McCoy's commission for the Enterprises emergency deployment for the V'Ger crisis. Kirk's plea,""Damn it, Bones, I need you--BADLY," ended McCoy's objection to the unwelcome "draft" and he returned to his frequent duty station, hovering just behind the captain's chair. ()
In 2285, McCoy advised a melancholic Kirk, while both were surrounded by Kirk's collection of genuine and simulated antiques, on his (Kirk's) birthday, "Get back your command. Get it back before you turn into part of this collection." He gestured to the collection and finished, "Before you really do grow old." ()
Kirk's drastic action taken to save Spock's katra was also an effort to save McCoy from the anguishing burden of bearing Spock's "marbles". After his moonlight requisition of the Enterprise resulted in the ship's destruction, burning through the Genesis planet's atmosphere, Kirk asked, "My God, Bones... what have I done?" McCoy replied, "What you had to do, what you always do: turn death into a fighting chance to live." ()
After the assassination of Klingon Chancellor Gorkon, Kirk and McCoy were imprisoned together on Rura Penthe. With the "help" of a shapeshifter named Martia, they were able to escape together and return to the Enterprise. ()