James Watt's 1769 patent is widely supposed to have stood in the way of the development of high-pressure steam technology until it finally expired in 1800. We dispute this popular claim. We show that, although it is true that high-pressure steam technology developed only after the expiration of...

In a patent infringement suit, the alleged infringer wins with a ruling of either patent invalidity or non-infringement. It is ambiguous which of these outcomes is preferred by the alleged infringer. Invalidity may increase current-period competition, but simultaneously removes constraints to...

I introduce and analyze an equilibrium model of discovery, innovation, patenting and infringement. Firms that innovate must adapt complementary inputs, and are ex ante uncertain about whether adaptations will be costly and whether they will infringe other patents. If adaptation requires...