This is the sixth case for Brazil's majestically imperturbable Captain Da Silva and while there are none of the exotic incidentals of the earlier books, the situation is very delicado: one of the delegates at an O.A.S. summit conference is to be killed. Then there's the steward, aboard a ship, a prospective appendectomy, who is flown ashore and disappears. All of the action takes place before rather than after the fact, and while the story itself isn't much more substantial than a fritos, still authoritatively handled.