Today we're talking about maps: why we can spend hours pouring over them, the stories they tell, the information they visualize, and how they border between map and a work of art is a gloriously fuzzy one. We spend the hour with journalists Betsy Mason and Greg Miller, co-authors of a beautiful and fascinating new book "All Over the Map: A Cartographic Odyssey". You can see some of the maps we discuss over at the All Over the Map section of National Geographic.