A patent is a grant from government that gives an inventor the exclusive right to make, use, and sell an invention for a period of twenty years from the date of filing the application for a patent. A copyright is the right to exclude others from using or marketing forms of expression. A trademark is the right to prevent others from using a company’s product name, slogan, or identifying design. Other forms of intellectual property are trade secrets (particular kinds of information of commercial use to a company that created it) and right of publicity (the right to exploit a person’s name or image). Note that the property interest protected in each case is not the tangible copy of the invention or writing—not the machine with a particular serial number or the book lying on someone’s shelf—but the invention or words themselves. That is why intellectual property is said to be intangible: it is a right to exclude any others from gaining economic benefit from your own intellectual creation. In this chapter, we examine how Congress, the courts, and the Patent and Trademark Office have worked to protect the major types of intellectual property.