The smallest businesses in America operate out of kitchens, garages, spare bedrooms, and folding tables on sidewalks, and they are subject to a surprising amount of law. This article explains the four layers that govern them: zoning and home occupation rules that decide whether the business may exist at the address, licensing that decides whether it may operate at all, food safety rules that decide what may be sold and where, and private restrictions from landlords and community associations that override everything else. It covers cottage food statutes and exactly what they permit and prohibit, mobile and sidewalk vending permits and the constitutional constraints on them, the insurance gap that leaves most home businesses uncovered, and the tax rules that reward accurate recordkeeping. It closes with the sequence a new home business should actually follow.