The Baron at Bay — John Creasey

Once the inheritance of a noble family, the five beautiful jewels of Castille were stolen, separated and their identity lost. Few men could recognize them for what they were, but John Mannering ' alias the Baron ' was such a man. In pursuit of jewels, Mannering has the misfortune to come up against three of the ugliest criminals he has ever met. To these men, robbery and violence are merely a game, and the Baron an inconvenient pawn who must fight for his life as well as the prize.