IntroductionThe term "Cold War" refers to the second half of the 20th century, usually from the end of World War II until 1990, when the Soviet Union Union collapsed. Since the 1940s and 1950s, scholars have disagreed on the topic of the origins of the Cold War. There are different groups of historians and their interpretations are very different, sometimes even contradictory. The three main schools are the orthodox, the revisionist and the realist. The classification is not entirely accurate because we can find numerous differences in scholars' theories within the same group and often the authors have reevaluated their ideas over time. The purpose of this article is to analyze each of the three main schools; present their main ideas and show the differences of opinion within each of them and also between the groups as a whole. To give some order to each school's individual ideas, I have chosen four main points that will help me understand each school's approach: 1) Who do they think is responsible for starting the Cold War 2) Where do they see the beginning of the Cold War 3) How do they see US foreign policy? 4) Dissenting opinions within each group. 5) The main authors and their ideas. I will only include the Western perspective. Covering the opinions of historians from all over the world would be really difficult in such a small space as this short essay. As I mentioned, there are three main schools. However, I liked to briefly mention ideas and authors that do not belong to any of these. Some writers look for the origins of the Cold War in events that occurred long before World War II. Desmond Donnelly interprets the Cold War as an imperial struggle. It finds its beginnings in the British-Russian context... at the center of the paper... and respected during the late 1940s and 1950s, when tensions began to intensify. This view dominated public opinion and scholarship in the West until the 1960s and helped justify US foreign policy. On the other hand, the revisionists found the cause of post-war tensions in the unnecessarily aggressive attitude of the United States. The third school is the so-called “realist” one. The scholars of this school do not attribute responsibility for the escalation of tension in the post-war period to any one party. They view the actions of both states as logical actions taken to maintain and improve their position. There are also other schools that emerged after the fall of the Iron Curtain and after the end of communist rule in the Soviet Union. There is still new information appearing in long-closed archives. And historians still do not have access to many of them.