I'm reading The World Guide to Beer by Michael Jackson at the moment, having picked up a cheap copy secondhand on Amazon.
I've had his Great Beer Guide for years and remember watching his Beer Hunter TV series in the late 80's. The World Guide to Beer is clearly a precursor of that series and like it covers beer styles from across the world. The book starts with graphs of the world's top beer brewing and drinking countries. That obviously doesn't tell you anything about how good the beer in those countries is. Off the top of my head, I can only think of six countries - Austria, Belgium, the Czech Republic, England, Germany and the Netherlands - where you're never far from decent beer.