Two years out of Princeton, a shy, fair-haired American on an airport runway meets a Middle Eastern monarch two inches shorter than her. Before long, Lisa Halaby has packed away her Dr. Scholl’s sandals, blue jeans, and plans for a journalism career to convert to Islam and become Queen Noor of Jordan. (She confesses she never has liked the name Lisa much.) An unlikely plot makes her memoir compelling, but the queen’s pride of purpose, largely untarnished by personal vanity, gives it stature. More interested in treaties than tiaras, Queen Noor chronicles her husband King Hussein’s long, bitter struggle for peace, cut short by his 1999 death from cancer. En route, she engagingly describes her uneasy adjustment to a court life so public that often she and her husband could confer privately only in their bathroom.