World systems theory was created by American sociologist Immanuel Wallerstein. In the early 1970s, Wallerstein began studying the history of economic and political relations between colonial powers and their colonies, and the results of this research are presented in The Modern World-System, vol. I: Capitalist Agriculture and the Origins of the European World-Economy in the Sixteenth Century (1974). In this book, he presents a new scientific paradigm that he calls "world system theory". This theory combines the theoretical positions of the dependency theory developed by Andre Frank and Samir Amin and the historical approach of Fernand Braudel. From the dependency theory,  Wallerstein adopted the view that it is extremely important to study the relations of unequal exchange between the countries of the center and the periphery, while from Braudel's approach, he adopted the principle that the unit of analysis should be the world economy, and that it should be studied with an interdisciplinary approach.

Wallerstein sees the world systems approach more as an epistemological perspective than as a macro theory. He rejects universalist theoretical explanations and promotes the historicity of all social sciences. Wallerstein also rejects supposed opposition of nomothetic aistorism, on the one hand, and ideographic historicism, on the other. Both of these epistemological approaches need to be combined into a perspective he calls the "historical system" in order to advance science.

After the publication of the first volume of the Modern World System, Wallerstein published three more volumes (1980, 1989, 2011), as well as many other books in which he further developed the theoretical, empirical, and methodological basis of his paradigm: World System Analysis: Theory and Methodology (1982a); Dynamics of the Global Crisis (1982b), The Politics of the World Economy (1984), Uncertain Worlds: A World-System Analysis in Changing Times (2013a). In these and other books, Wallerstein collaborated with other authors who accepted his paradigm - Samir Amin, Andre Frank, Giovanni Arrighi, Terence Hopkins, Etienne Balibar, and others. In his four-volume book The Modern World System, Wallerstein successively analyzes the historical development of the world system from the beginning of the sixteenth century to the beginning of the First World War.

                                          World-Systems

Wallerstein's basic theoretical starting point is that throughout history, individual societies have always been economically, but also in other ways, connected with surrounding societies, so it is necessary to study the systems of connected societies and their interactions to understand the causes and dynamics of social change. He calls all such systems of a large number of connected societies "world-systems". Wallerstein defines the "world-system" as a group of different societies united by a differentiated system of unified division of labor. Such a system must be able to meet the basic needs of most people, by production and exchange within the system itself. Societies that make up the world system do not have to be politically united, moreover, they can have very different political systems and cultures. What unites them is the unique division of labor within the system itself.

Throughout history, there have been three different types of social systems with a common division of labor. The first type concerns small and homogeneous societies, the so-called "mini-systems" of hunter-gatherers and primitive farmers united by the reciprocity-based economic exchange. The second type is "world-empires", which is characterized by a unique political system in which the center of the empire, which has political-administrative and military power, appropriates the surplus values ​​created by oppressed classes and conquered peoples and regions. World-empires are characterized by great military and administrative costs, so they constantly have to wage new wars of conquest in order to survive. World-empires are constantly going through periods of growth and decline, and the best examples are the Roman Empire and the Chinese Empire.

                                    World-Economies

The third type of world system is the "world-economies", which consists of a large number of politically independent units that are all economically integrated through trade and division of labor. All the products necessary for the survival of the world-economy are produced within it, but since different political units of the world-economy produce different products, which is the basis of the division of labor, it is necessary to redistribute these products through trade. World economies in the past were short-lived, as they were usually disintegrated or integrated into world-empires. The current world-economy, which has survived to this day, emerged at the end of the Middle Ages in Europe. At that time, a complex trade network of agricultural products was created, and the most important role in that trade was played by trade cities, among them those in the Netherlands, and the Hanseatic League were especially important. The world-economy, which existed in Europe at that time, was surrounded by world empires, which gradually, as they lost power, became integrated into the world-economy. The centers of development of the world-economy in the modern era were England, the Netherlands, and France. The development that took place in these countries created the basis for capitalist industrialization. By the end of the nineteenth century, this world economy, through colonialism and imperialism, had spread to the entire planet, and the engine of its expansion was the constant need for the accumulation of capital.

The world-economy is characterized by three different sectors, which Wallerstein calls the periphery, the semi-periphery, and the center. Each of these sectors contains several different states. The center consists of the most technologically developed and richest countries, which appropriate the greatest benefit from the way the whole system is organized. The countries of the center shape the world system itself and the patterns of investment and trade. There is always a struggle between the states of the center for power and the accumulation of capital. The states and colonies located on the periphery are exploited, through trade relations, by the countries of the center, and this exchange produces the subordination of the states of the periphery. Both development and underdevelopment are interdependent processes because the development of the countries of the center necessarily depends on the underdevelopment of the countries on the periphery.

The states of the semi-periphery, by their characteristics and position, are located between the center and the periphery and may include former countries of the center, whose position has declined or countries originating from the periphery, but whose position has improved, so they moved to the semi-periphery. While the countries of the center often advocate a free world market, the countries of the semi-periphery prefer the tactics of protectionism.

Belonging to a sector affects many characteristics of a certain state or territorial unit: average life expectancy, living standard, position and control over the labor force, type of products intended for foreign trade, type of political regime, etc. The position of the labor force and the control over it are directly related to the type of production intended for foreign trade. The periphery produces and trades mainly with raw materials, and the labor force is poorly paid and subject to great control (whether the labor force has a formal-legal position of slaves, serfs, or free workers, it does not change its essentially extremely bad position of workers in the periphery), while the countries of the center produce and export finished products, and the wages of the labor force are higher, while the control over it is less strict.

The growth of capitalism depends on the potential to constantly increase the accumulation of capital, and such accumulation necessarily depends on the possibility of incorporating new territories into the world-system. It is this fact that led to the creation of the world-economy. Capitalism also tends to subjugate the policies of all states to its own interests, so most capitalist profits come through quasi-monopolies guaranteed by states. The world-economy is dynamic, and long-term economic cycles (of which the Kondratieff's cycle is the most important), geopolitical relations, as well as internal economic dynamics, are the most important factors influencing the decline or progress of a country from one sector to another. The dynamics of the world system are also influenced by the resistance of the periphery and semi-periphery, anti-systemic movements (anti-colonial, socialist, for minority rights, etc.), class relations, but also race and gender relations.

The modern world-system possesses what Wallerstein calls "geoculture," a value system that covers the entire planet. The main feature of this geoculture is "centrist liberalism" which emphasizes the values ​​of universalism, equality, and meritocracy. On the other hand, the very structure of the system promotes particularism. Conflicts between states and ethnic conflicts within states promote nationalism, division into center and periphery encourages racial divisions, while the economic survival of poor households around the world depends on the sexist exploitation of unpaid women's labor.

                Globalization and Rise and Decline of the USA

Wallerstein also studies the historical course of the rise and fall of power in the most important states of the center. He sees the whole period, from the beginning of the First World War until the end of the Second World War, as one great war, the goal of which was to determine the successor of Great Britain as the most important state in the center. At the end of World War II, the United States emerged victorious and became the absolute leader of the center. On the other hand, after the war, the Soviet Union became the most important state of the semi-periphery, which did not represent true communism but advocated protectionism. Wallerstein states, in Decline of American Power (2003), that the rise of anti-systemic movements in the center and periphery, along with protests around the world in 1968 and the US defeat in Vietnam, led to the defeat of the classical liberal paradigm and the decline of US power.

Wallerstein sees the process of globalization more as part of a great economic cycle than as a radical transformation of the international economy and politics. He believes that it is necessary to study the similarities and differences that exist in the waves and cycles of international trade and international investment in the last two centuries, in order to understand globalization. In the last few decades of the twentieth century, the internationalization of capital took place, which limited the power of nation-states to control their own economies. On the other hand, states have long been influenced by broader geopolitical and economic relations and processes taking place within the world-system. Economic integration has had long cycles of decline and growth over the past few centuries, and the current phase is only the last phase of a very long systemic cycle of accumulation. What marks globalization is the increase of global economic integration, primarily through the increase of international trade, financial flows, and foreign investments.

                  Other Proponents of World Systems Theory

Italian political economist and sociologist Giovanni Arrighi collaborated with  Immanuel Wallerstein on the topics of international capitalism and world systems theory. In the book Geometry of Imperialism (1978), Arrighi states that imperialism, which is a war between capitalist countries, is a necessary consequence of the transformation of classical capitalism into monopoly and financial capitalism. Arrighi showed that at the end of the twentieth century, there was an increase in the working class at the world level, although at the same time, there was a numerical decline in the working class in rich countries. Workers in developed countries are facing declining wages and increasing competition due to immigrants willing to work for lower wages.

In his book The Long Twentieth Century (1994), Arrighi deals with the history of international capitalism from the 14th century to the present day. He believes that financial capital has been a central component of the world system all that time. Current cash flows have the typical characteristics of very long "systemic cycles of accumulation". The new imperialism of rich states, which emerged in the twentieth century, contains two connected logics: the territorial logic of political power and the molecular logic of capitalist accumulation. That is why war is a means by which the United States ensures its hegemony over energy resources and thus increases its importance in the world economy.

American sociologist Janet Abu-Lughod wrote the book Before European Hegemony: The World System A. D. 1250-1350 (1989), in which she studied the emergence of the world system before the emergence of European hegemony. She pointed out that the Mongol Empire contributed to the unification of China, India, Muslim countries, and Europe into a single political and economic system. This world system consisted of eight subsystems, which were gathered around three main centers - Western Europe, the Middle East, and the Far East.

American sociologist Christopher Chase-Dunn is the founder of the Journal of World-Systems Research. He continued to develop world-systems theory, extending it to earlier periods and introducing the concept of a mini-world-system, which he developed by studying the Wintu people of Northern California. In the book Rise and Demise: Comparing World – Systems (1997), he presents the thesis that the states that were on the periphery of the world system, and were heading towards the center, were the main cause of the formation of empires and the development of trade. A similar process is happening today in Mexico, India, South Korea, and Brazil, which could lead to the transformation of the current global system.

Authors: Abu-Lughod, Arrighi, Chase-Dunn, Frank, Wallerstein. Ekholm Kaisa, Friedman Jonathan, Hall D. Thomas, Hopkins K. Terence, Modelski George.

Books:

Abu-Lughod, Janet. Before European Hegemony: The World System A. D. 1250-1350 (1989);

Arrighi, Giovanni. Geometry of Imperialism (1978);

     -     The Long Twentieth Century (1994);

Chase-Dunn, Christopher. Rise and Demise: Comparing World – Systems (1997);

      -     Global Formation (1998);
Chase-Dunn, Christopher and Thomas D. Hall. Rise and Demise: Comparing World-Systems (1997);
Frank, Andre Gunder. The World System: Five Hundred Years or Five Thousand? (1996);                                               -     Riorient (1998); 
McMichael, Philip.Development and Social Change: A Global Perspective (2000);
Modelski, George and William R. Thompson. Leading Sectors and World Powers (1996);
Shannon, Thomas R. . An Introduction to the World-Systems Perspective (1996);                                         Wallerstein, Immanuel. The Modern World System, Vol. 1 (1974);

     -     The Capitalist World Economy (1979);

     -     The Modern World System, Vol. 2: 1600–1750 (1980);

     -     World-Systems Analysis: Theory and Methodology (1982);

     -     Dynamics of Global Crisis (1982);

     -     Historical Capitalism (1983);

     -     The Politics of the World-Economy (1984);

     -     The Modern World System, Vol. 3: 1730–1840s (1989);

     -     Decline of American Power (2003);

     -     The Modern World-System, Vol. 4: 1789-1914 (2011);

     -     Uncertain Worlds: World-System Analysis in Changing Times (2013).