Europhiles who are skeptical about the ability of Napa Valley Cabernet Sauvignon to age gracefully are especially likely to assume that warm, early vintages can't possibly last. But on my early spring visit to Napa Valley, a major horizontal tasting of the 2004s demonstrated that that was not the case. Not only were very few wines showing signs of age, but the best examples are developing at a snail’s pace and will continue to improve with more time in the cellar.