The Dangerfield Talisman

In the first place there was the Dangerfield Talisman, an ancient golden armlet set with diamonds and valued at $50,000 - an unguarded treasure, which, although stolen more than once, always came back. Second was the Dangerfield Secret. The last thief of the talisman has been found on the lawn of Old Rollo Dangerfield's home, dead of a heart attack. And in unearthing the mystery a whole series of bewildering complications unfolds ... 'Specially ingenious' Observer