Patents play a critical role in business, society and technological innovation in the contemporary knowledge economy. The question of what types of inventions may be patented, however, has become highly contentious in patent offices, law courts, legislatures, scientific organizations, international trade forums and various business or social advocacy groups around the world. Under what conditions-if any-may computer software, DNA-based products, new business techniques, medical diagnostic methods, or systems operating over the Internet, for example, be patented? Conflict and confusion in the...