A freedom-to-operate (FTO) or Right-to-Use Search or Right-To-Market or Clearance Search is a search done on issued patents or on pending patent applications to determine if a product or process infringes any of the claims of the issued patents or pending patent applications. A clearance search may also include expired art that acts as a ‘safe harbour’ permitting the product or process to be used based on patents in the public domain. These searches are often performed by one or more professional patent searchers who are under the direction of one or more patent attorneys.