Chapter 4 reviews the history of the OSCE after the end of the Cold War, emphasizing its significant institutionalization in the decade of the 1990s, followed by the gradual decline of its role in the early years of the twenty-first century. It discusses a series of conferences, beginning with the signing off the Charter of Paris in 1990, followed by the 1992 Vienna Summit of OSCE heads of state, through the last Summit in Istanbul attended by the heads of all participating States in 1999, with the number of participants increasing from 35 to 57, as all states emerging from the breakup of the Soviet Union, Yugoslavia, and Czechoslovakia joined the OSCE as independent and sovereign states. During these years, regimes focusing on arms control and human rights expanded greatly, as did OSCE institutions to manage these broad dimensions of security “from Vancouver to Vladivostok the long way around.” The OSCE also changed from a series of “conferences” to a full-scale organization with a Secretariat in Vienna and specialized offices in Warsaw, the Hague, Copenhagen, and Geneva. Of special importance to the focus of this book in all subsequent chapters was the creation of the OSCE Conflict Prevention Centre in Vienna, which managed “missions of long duration” in regions experiencing conflict. It concludes with an analysis of the challenges to finding consensus among OSCE participating States regarding many issues, especially the war in Ukraine, which put the very survival of the institution at risk as it reached the 50th anniversary of the Helsinki Final Act in 2025.