The analysis extends beyond the standard case of the monopolist who integrates in order to isolate some of his customers from arbitrage in the monopolized good so that he can discriminate against them. It examines the exploitation of factors employed by, and the customers of, the monopolist's customers. By vertical integration the monopolist may utilize barriers to arbitrage that would otherwise be unexploited because the market is competitive. Sometimes looser forms of vertical control, for example, tying arrangements, can be employed, and in some circumstances it is possible to extract surpluses from parties with whom the monopolist does not trade.

The analysis extends beyond the standard case of the monopolist who integrates in order to isolate some of his customers from arbitrage in the monopolized good so that he can discriminate against them. It examines the exploitation of factors employed by, and the customers of, the monopolist's customers. By vertical integration the monopolist may utilize barriers to arbitrage that would otherwise be unexploited because the market is competitive. Sometimes looser forms of vertical control, for example, tying arrangements, can be employed, and in some circumstances it is possible to extract surpluses from parties with whom the monopolist does not trade.

A recent synthesis and development of the literature by Smith (1969) has greatly increased the power and generality of the economic theory of commercial fishing. In contrasting his own analysis with previous work, Smith suggests that the most serious deficiency in the received doctrine is that it "is not able to handle the situation in which a species may be exploited to the point of extinction. The theory implies that short of zero unit costs the equilibrium yield to competitive exploitation is never zero with an extinct population." As Smith observes, evaluation of this implication depends on whether one believes that commercial fishing has ever, or could ever, cause the extinction of a fishery a matter over which there is some controversy.' The theoretical question is one of importance from both positive and normative points of view. On the one hand, it would appear that, if convincing evidence of commercial extinction were discovered, then the received theory of fishing would be decisively refuted. On the other hand, policy makers cannot wait indefinitely for the results of future research, especially when concerned with irreversible changes such as the extinction of species. Their attitudes toward proposals for the regulation of fishing are bound to be colored by untested conclusions of current theory. For these reasons, it would seem important to reexamine the inference which Smith draws from the received theory, particularly because Smith does not explain which features of the theory are responsible for his conclusion.

Costs must be incurred if an owner is to enforce private property rights effectively. We show that, in a perfectly competitive economy, private decisions to enforce rights may result in either more or less enforcement than is socially efficient. Cases of multiple stable equilibria occur, and an equilibrium may be locally, but not globally, efficient. Resources may not be employed in their socially most valuable uses, and enforcement may be accompanied by inefficient investment in resource productivity.

Costs must be incurred if an owner is to enforce private property rights effectively. We show that, in a perfectly competitive economy, private decisions to enforce rights may result in either more or less enforcement than is socially efficient. Cases of multiple stable equilibria occur, and an equilibrium may be locally, but not globally, efficient. Resources may not be employed in their socially most valuable uses, and enforcement may be accompanied by inefficient investment in resource productivity.

Distributions of income are compared under the alternative regimes of free access to, and private property in, a resource. It is shown that, in several analytically distinct cases, all those deprived of free access on conversion of a resource to private property can be better off, even though no compensating transfers are made. This resu lt can hold even if the granting of private property rights also conf ers monopoly or monopsony power.