ON BOXING DAY I was in the Borghese Gardens, where I thousands of courteous Romans promenaded the avenues in their fur coats. Two children had escaped into a grove of his Renaissance garden into a miniature Arcadia inspired by the landscape gardens at Rousham and Stowe.

Why would a Roman prince ask a British painter to design a mock-Classical temple in a city so 111 of real ones? The subject of this new book is the mania for the Enghsh Picturesque garden in eighteenth-century Europe. In every country, parterres and flowerbeds imitating Versailles were replaced by