IntroductionThe term "Cold War" refers to the second half of the 20th century, generally from the end of World War II until 1990, when the Soviet Union The Union collapsed. Since the 1940s and 1950s, scholars have disagreed on the question of the origins of the Cold War. There are several 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 one can find several differences in researchers' theories within the same group and often authors have re-evaluated 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 but 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 believe was responsible for starting the Cold War 2 ) Where do they see the start of the Cold War? 3) How do they view American foreign policy? 4) Dissenting opinions within each group. 5) The main authors and their ideas. I will only include the Western perspective. It would be very difficult to cover the opinions of historians around the world in a space as small as this short essay. As I mentioned before, there are three main schools. However, I enjoyed briefly discussing ideas and authors that do not belong to any of them. Some authors look for the origins of the Cold War in events that occurred well before World War II. Desmond Donnelly interprets the Cold War as an imperial struggle. It originated in the Anglo-Russian conflict...... middle of paper ...... popular and respected in the late 1940s and 1950s, when tensions began to escalate. This view dominated Western public opinion and academics until the 1960s and helped justify American foreign policy. On the other hand, revisionists found the cause of postwar tensions in the United States' unnecessarily aggressive measures. The third school is called “realistic”. Specialists from this school do not reject responsibility for the escalation of tensions after the Second World War. They view the actions of both states as logical actions aimed at retaining and improving 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. New information is still emerging in the long-closed archives. And to many of them, historians still do not have access.