In the past, the development and commercialization of an innovation process used to depend on intra-organizational think-tank and efforts. Today, however, Open Innovation paradigm calls companies to also tap into outside ideas and technologies and yet mutually allow other companies to exploit their innovative ideas. Open Innovation is a hot topic which has outstandingly drawn researchers' and managers' attention from various perspectives in the past few years. Therefore, reviewing on a case study basis, the topic's entire literature that comprises 70 papers, the current research paper aims to cover its concepts, approaches, major trends, and key success factors. To point to a few findings of the research, the paper dramatizes new and emerging perspectives and trends in the realm of Open Innovation, successes like external networking, innovation brokers, technology intelligence, absorption capacity, open business model, and human factors such as culture and motivation. The paper concludes that managers of companies and organizations should exploit Open Innovation as a solution to confront fast changing technological trends, short technology life cycles, high internal R&D costs, and sever global competition.