A patent is a legal title that gives the holder the right to exclude others from using a particular invention. If the invention is successful on the market, the patent holder will profit from its monopoly power. Patents therefore allow inventors to internalise the benefits they generate. Without such a mechanism, inventions could be imitated, which would reduce inventors’ return on their investment. Patents are granted in return for disclosure of the invention and therefore play a role in the diffusion of knowledge. Inventors and firms apply for patents at patent offices, which grant or reject patents for their jurisdiction, mainly the domestic market, in accordance with their legal statutes. Most patent offices are national organisations; the main exception is the European Patent Office (EPO).