“The New Girl” is a raven-haired beauty who stands out evenmong her classmates at an exclusive private school in Switzerland for her evident wealth and remote mien. She is said to be the daughter of a wealthy international businessman, but in truth, her father is Khalid bin Mohammed, the crown prince of Saudi Arabia.   And when she disappears from campus, the prince turns not to his own agents but Gabriel Allon, the head of Israel in intelligence, to find her. LP and CD copies are also available.