In the fascinating new book Mine! How the Hidden Rules of Ownership Control Our Lives, law professors Michael Heller and James Salzman explore ways in which complicated rules of ownership shape our world. They demonstrate clearly that a possession instinct extends far beyond conventional categories like “my car” or “my land” or “my money.” In fact, numerous ownership battles regularly intrude on everyday life. If you own a brick-and-mortar restaurant with all kinds of overhead costs and a mobile food truck pulls up to do business outside your bistro’s front door, who has occupancy rights to that valuable space? If the water supply for your house is dependent on a well you’ve dug, do you own that subterranean water or does your neighbor? It may not be an urgent question until the neighboring farm or production plant contaminates the underground aquifer.