A shapely memoir and meditation by the great poet and author of The Lost Upland: Stories of Southwest France. Merwin -- who has had a farmhouse in the region for decades -- writes of rural traditions, his own love of the region, and, specifically, of the narrative poems and songs of the troubadours. The title refers to the ruined 12-century chateaux of Bernart de Ventadorn in southern France. A book in the series National Geographic Directions.  (FRN341, $20.00)