I've been enjoying one of my birthday gifts a lot recently. A bought me a copy of The Wine Atlas, and it has a lot of great general information on wine and grapes, as well as detailed maps of the great wine-producing regions of the world.
The southern hemisphere gets a bit of a short shrift (as usual), especially South Africa, which gets very few pages and only a map of the Paarl region. (What, no Stellenbosch, Franschoek, not to mention the other up-and-coming regions in the Western Cape, like Durbanville?)
Possibly one reason that the book spends less time and paper on the southern hemisphere (and even the USA) is that "new world" wines are much easier to understand simply by looking at the label. You'll usually be able to tell (unambiguously) the winery, grape type, vintage, and area the wine comes from. The back label will usually tell you even more (like climate conditions in the year of harvest, wine-making technique used, type and length of barrel conditioning, etc.)
Old-world wines are much more confusing. Most label have no grape type listed. Instead you'll get the chateau/winery name (sometimes), sometimes with a whimsical name, the vintage, and appellation/regional origin. The appellation, if you have an encyclopedic knowledge, will tell you what grape type(s) are used, and usually the style of wine.
Having the atlas means I've actually been able to begin to understand where the various French AOC/Vin de Pays and Italian DOC/DOCG regions actually are, what wineries are part of them, and what rules regulate the wine made there.
For example, take a recent French wine I drank: 2003 Domaine des Baumard Anjou Clos de la Folie. It's quite fun being able to look up the Anjou region in the atlas, read about the history and traditional wines made there, and see maps of the towns and vineyards/chateaux. I also found out that Anjou is mainly known for its rose and white wines, but that more wineries are experimenting with red wines nowadays.
For Italian wine, the atlas helps to seperate wines with similar-sounding names, like Montepulciano d'Abruzzo versus Vino Nobile di Montepulciano. It was also fun to look up Asti and see the familiar winery names (like La Serra, which belongs to Marchesi di Gresy).
It would be cool if there was an online wine atlas. (Google Maps or Virtual Earth maps overlaid with winery and vineyard info? Region names and borders, AOC/DOC/DOCG info. Maybe a nice mash-up to try to implement in the future?)