The book presents, in a light-hearted way, a set rules for how things should be done in a shared home or apartment, e.g., loading the dishwasher, drinking out of the milk carton, sink eating, the toilet seat controversy, and many more. The theme of the book is that these are petty things and the "right"way might be just the way a person grew up with. Instead of engaging in an argument that can't be won, go to the Rule Book and look it up. Sometimes the rule will seem to favor one party, sometimes another, but that's not important. The book quotes Thomas Jefferson in the frontispiece "It is much more material that there is a rule to go by than what the rule is."