With its steep hillsides, clay-limestone soils, and legions of passionate devotees, Sancerre remains at the pinnacle of Sauvignon Blanc in the Loire, if not the world. This is the style of Sauvignon Blanc that has set the bar to which all other versions of that animated grape aspire. But hardly to be forgotten are the astonishing wines of its next door neighbor Pouilly-Fumé, where the silex soils lend subtle and engaging aromas of gunflint to the wines.