Great wine guide. It's very similar to Hugh Johnson's pocket guide but with much greater detail.
Talking of Hugh Johnson, this guide suffers from the demon proof-reader too - perhaps they've all been sampling too much vino! Unless you've got a fantastic memory, Hugh Johnson's guide is probably more useful as it can easily be carried around on wine buying trips, Wine Behind TL is really too bulky for that.
Wouldn't be without it though. It's encyclopedic knowledge will help you track down the wines that you want.