Check out Slate's review of Along Those Lines (with this great illustration by Eleanor Davis).
It's fun to spend a few hours in the presence of an amateur geographer whose brain is crammed with birds and pop songs and bits of string. The end effect of Along Those Lines is of having dipped into a long-running notebook, a very pleasant one, from a person who would truly like to know how all the human systems work but has also accepted that perfect knowledge will never come. He's going to do his best and not pretend to have all the answers. Cashwell doesn't have a focused thesis about human territoriality. He wants us to open our eyes to borders, but he doesn't tell us what to do about them. Just seeing them is enough, perhaps.