I'm sure that's the book the poster was referring to. I read it when it first came out - it's right on the mark. The books geographical divisions are much more realistic than state lines. Northern Indiana and Ohio have much more in common with Southern Michigan than the southern sections of those states have much more in common with Kentucky & Tennessee than they do with the northern parts of those states.
Do yourself a favor and read this book - its very interesting.
It was one of the main texts for an Economic Geography course I took some years ago as an elective course.