This chapter discusses patents, which are granted for new and inventive technological developments but not for developments in the creative or non-technological arts. Areas on the borderline between technical and other forms of creativity are the subject of difficulty and controversy. Patents last for 20 years from application, but may be revoked at any time on the grounds that the invention does not meet the requirements for patentability. Manufacturing or dealing in products, or carrying out processes, as described in the patent’s claims, infringes the patent. Unlike copyright, where both economic and individual rights are important, the main reasons for the grant of patents are economic, to encourage technological development. Patents are considered essential to many industries such as the pharmaceutical industry, where there is also a strong public interest in the development and accessibility of technology. The law must strike a balance between the public and private interests.