This document presents the main concepts related to patents and to the patenting procedure. The goal is to provide expert and non-expert readers with concise information needed to interpret correctly patent analyses. The document explains what is a patent, the difference between a published patent application and a granted patent, and the patenting routes including regional, national and international phases. The document then focuses on PATSTAT, the European Patent Office’s (EPO) Worldwide Patent Statistical Database, and discusses the availability of patent data. This section indicates how to make the correct choice in terms of reference date and to answer the right research question. Every research question generates a different time lag in patent analyses. The documents concludes by presenting the JRC patent methodology, applied in the context of the Strategic Energy Technologies Information System (SETIS) of the European Commission, to monitor Research, Innovation and Competitiveness (RIC) in the energy sector.