Star Trek: The Next Generation: Stargazer: Oblivion

Captain Jean Luc Picard accepts a courageous mission which he soon finds could be a deadly trap in this Star Trek: The Next Generation novel. In 1893 a time-traveling Jean-Luc Picard encountered a long-lived alien named Guinan, who was posing as a human to learn Earth's customs. During this "first encounter," Picard saved Guinan's life, a favor she would never forget. Five centuries later, Captain Picard, now commander of the Starship Enterprise ™, brought Guinan aboard as the ship's "bartender.