Each map in the actual book has a page of text accompanying it and it usually explains what the shaded areas refer to. As I recall, the absence of a name is mea

Each map in the actual book has a page of text accompanying it and it usually explains what the shaded areas refer to. As I recall, the absence of a name is meant to imply a pre-state, tribal zone, and the different patterns indicate the basic cultural-linguistic group involved (i.e., diagonal lines = eastern European Slavic tribes, etc).