A patent examiner (or, historically, a patent clerkThe title "patent clerk" is used for instance in Gary Stix, The Patent Clerk's Legacy, Scientific American, September 2004 (an article about Albert Einstein)) is an employee, usually a civil servant with a scientific or engineering background, working at a patent office. Major employers of patent examiners are the European Patent Office (EPO), the United States Patent and Trademark Office (USPTO) and the Japan Patent Office.