The Island of Sheep is a 1936 novel by the Scottish author John Buchan, the last of his novels to focus on his characters Richard Hannay and Sandy Arbuthnot
Twelve years on from the last novel in which he featured, Richard Hannay, now in his fifties, is called by an old oath to protect the son of a man he once knew, who is also heir to the secret of a great treasure. Helped by old friends, Sandy Arbuthnot, now Lord Clanroyden, and Lombard, the action takes place in England, Scotland and on the Island of Sheep.
An engaging adventure set in some unusual locations. Definately worth a read.