Open sources contain publicly available information at a low cost. The amount of open source information an individual has access to has increased dramatically in the 21st century. The question is how to evaluate these diversified open sources in producing intelligence- supporting the policymakers in making their decisions by providing them with the necessary information. To retrieve the actionable intelligence from huge amounts of open source information, and to do source validation are big challenges. In this book, an open source intelligence (OSINT) integrated intelligence model is proposed, and compared with the traditional intelligence model. The contemporary intelligence analyst and his OSINT making process is discussed. A case study of OSINT is presented, analyzed and the analysis results are given. The work discusses the varying procedures involved in the OSINT tasks and the need for metrics, and should be useful to information professionals, analysts, decision makers, or anyone else who needs to do analysis on data.