Intellectual property (IP) rights have long been a topic of passionate debate among libertarians. This chapter does not take sides in this debate. It describes what IP rights are, details their historical evolution and legal status, and then surveys the arguments justifying or critiquing IP rights. The chapter primarily focuses on the moral justifications and critiques of IP rights, which are usually derived from two theories: natural rights and utilitarianism. Objectivism offers a third approach in justifying IP rights. The justifications for IP rights focus on securing to individuals the fruits of their productive labors (natural rights), securing the values created by the rational mind (Objectivism), or increasing net social welfare by incentivizing creative work and new commercial activities (utilitarianism). The critiques of IP rights begin with the factual claim that ideas are not scarce; accordingly, in the context of new ideas, there are no disputes over scarce resources requiring property rights as a mediating standard. Thus, IP rights are monopoly grants that violate the rights of liberty and property (natural rights) or undermine social welfare given the high costs of economic deadweight losses and of rent-seeking, strategic behavior (utilitarianism). In describing these justifications and critiques, the chapter highlights key topics in the IP debates, such as term limits for patents and copyrights. It also addresses responses to these respective justifications and critiques. A single chapter cannot cover every legal, historical, or moral issue, and thus the list of references identifies historical and contemporary sources for further study.