An exciting discovery in the laboratory may translate to a commercial product. How does the patent system fit into the picture? We first discuss the circumstances under which an invention is granted a patent. What is the purpose of a patent and what are the functions of the patent system? Who can apply for a patent? What makes an invention patentable? A patent does not automatically grant a right to make or sell a product. This is because multiple patents can cover a single pharmaceutical product. Understanding the patent landscape covering a product of interest is key to evaluating the risk of infringing another's exclusivity rights. We use a hypothetical example relating to skin cancer to guide a discussion of patent law.