Since Agatha Christie is so pre-eminently the mistress of the straight detective story, we're apt to forget how good she can be on her occasional ventures into the spysuspense-intrigue novel. And so well has she exploited the English countryside that we may also forget how intimately she knows the Middle East. These two neglected facets of Miss Christie glisten brilliantly in ["They Came to Baghdad"]. This is a story of little detection or mystery, but much intricacy and surprise, revolving around the preparations for a top level East-West conference in Baghdad and the machinations of a new kind of international intrigant who makes the Fascists and Communists of the average thriller seem almost innocuous. All of this is embellished by authentic first-hand details on Iraq archaeology and the fine, easy sketching of a large cast. All in all, the most satisfactory novel in some years from one of...