Prior art searches are really important to avoid "reinventing the wheel", infringement to third parties rights, but also to write a better patent application, to speed up the prosecution of an application, to find out the most recent inventions and to study technological trends. There are many type of searches: informative patentability validity (opposition) legal status freedom to operate (FTO) The scope of a patent search is to find documents that claim similar technical features and not a mere match of words. Patent searches can be carried out by: keywords classification symbols (IPC, CPC codes) citations