Mission to Siena

For years, the operations of a mysterious and ruthless extortioner, who called himself “The Tortoise”, had baffled Scotland Yard and the police forces of Europe. But the Tortoise made a mistake of interfering with Don Micklem, millionaire settled in London, with friends in high places. And once Micklem was aroused, he tracked down the Tortoise to his lair in a remote place in Italy….