Unlike publications in scientific journals, patent applications are not sent to reviewers for comments on technological aspects. Patent applications are assessed by patent examiners, who, in the major jurisdictions, have both a technological and legal background. They determine whether a filed invention meets the patentability criteria: mainly novelty and non-obviousness or inventiveness. Patent examiners utilize their technological and legal skills to search for prior art (written documents published worldwide, relevant to the filed invention). Their task is to establish whether the invention has been previously described and whether it could have been obvious to a person of ordinary skill in the field of the invention. Whether a granted patent is scientifically or technologically valid is established by the final users of the patented invention.