"Dr. McCoy is surprised to learn that his ex-wife, now remarried, is one of the mediators. But before he can begin to face his feelings, she and captain Kirk are trapped by a band of deadly assassins. Suddenly, McCoy is at the center of an explosive civil war, where he is the only one with the power to save the woman who once broke his heart."@en
"As a young doctor with a beautiful family and a promising medical career, Dr. Leonard McCoy thought he had it all. But when the woman he loved betrayed him, McCoy fled to Starfleet, hoping to lose his pain in the depths of space. Now, more than forty years later, the EnterpriseTM and her crew are ordered to transport a group of mediators to the planet Ssan, a world where assassination is a time-honored tradition, and McCoy is surprised to learn that his ex-wife, now remarried, is one of the mediators. And before he can come to terms with his conflicted feelings for his former love, she and Captain Kirk are trapped on Susan, and McCoy is caught in an explosive civil war, the only one with the power to save the woman who once nearly destroyed him."@en
"A treat for Trekkers everywhere--the long-awaited novel that explores the life of one of Star Trek's most beloved characters, Dr. Leonard "Bones" McCoy. Follow McCoy from his first days as a junior Starfleet medical officer to his position as Chief Medical Officer of the Federation's flagship ... where he must save his ex-wife from death."@en

Star trek : shadows on the sun