Abstract
Although regionalism is a long-standing feature in international relations only since the 1960s and more emphatically since late 1980s scholars have shown a dedicated interest in the phenomenon. The literature is nonetheless disarticulated. This article takes one step back to take two steps forward. First it clarifies commonly used terms in the field as region, regionalism and regionalization and spells out its historical context. Second it focuses on the past by elaborating on the theoretical approaches put forward over the last fifty years and by highlighting the topics that concerned scholars. Thirdly, it channels attention to the future of regionalism introducing a tentative agenda for research where issues as regionalism and peace, micro-regionalism, in/out regional mechanisms, inter-regionalism, and the role played by the United States gain a particular relevance.