The Messenger by Daniel Silva

Very good and a good series. PW: starring Israeli art restorer and spymaster Gabriel Allon. Ahmed bin Shafiq, a former chief of a clandestine Saudi intelligence unit, targets the Vatican for attack, in particular Pope Paul VII and his top aide, Monsignor Luigi Donati, who both appeared in Silva's previous novel, Prince of Fire. Shafiq, who now heads his own terrorist network, is allied with a militant Islamic Saudi businessman known as Zizi, a true believer committed to the destruction of all infidels. Gabriel's challenge is to infiltrate Zizi's organization, a task he assigns to a beautiful American art expert, Sarah Bancroft. Gabriel promises he'll protect her, but plans go awry, and by the end Sarah faces torture and death.