Chapter 10 identifies 21 variants of the good-faith purchase doctrine, which are often different combinations of several key factors. That said, none of the 21 schemes are the most efficient. Among the forms of good-faith purchase doctrine currently in use, the market overt rule comes closest to ex ante efficiency because original owners, merchant dealers, and consumers all have incentives to spend close to optimal costs on verification and prevention, and the movables in question are more likely to be in the hands of higher valuers. Drawing on mechanism design literature, Chapter 10 argues that when both an original owner and a consumer are non-negligent, the two parties can be assigned 50% shares of the movable in question, and an ensuing internal auction between them can ex post tease out who values the resource more. This internal auction design is inexpensive to administer.