Social Systems are paradigmatic examples of complex systems. Its evolution over time cannot be explained by the procedure of understanding the behavior of the constituent parts of the phenomenon and from there elaborating an explanation of the system as a whole, since the interaction between these parts is an essential factor of the internal dynamics thereof. Hence, the famous mantra that the whole is much more than the parts.¹ They also have structures at various hierarchical levels and knowledge of the interaction between their microscopic parts is sometimes not enough to elaborate an explanation of their macroscopic observables. While the development of modern complex systems theory is an offspring of the last decades of the last century, some of these features were glimpsed long before by social scientists. Such is the case of A. Smith, whose invisible hand represents the description of an emergent property of those complex systems that encompass the economic interactions of our societies.

It is not strange then, that in the middle of the 60s of the last century in the area of human and social sciences in particular a research paradigm known as structuralism was developed. This theoretical movement that began in France is a methodological approach that states that in every social system there are a series of structures that determine its evolution.

The seed of this theory must be sought in earlier times with Ferdinand Tönnies for example. He used the concept of social structure to explain the systematic relationships that link members of a certain community. He argued that members of social groups can establish personal and direct ties that link them with those who share values and beliefs and that there may also be formal and instrumental social ties. E. Durkheim provided a non-individualistic explanation of social phenomena by arguing that they arise when the interacting individuals constitute a reality that can no longer be explained in terms of the attributes of the individual actors. It should be noted that Durkheim here clearly stated the existence of an emergent property in the sense of modern complex systems theory. Both Durkheim and Tönnies made intuitive use of this concept. It was Georg Simmel who, at the beginning of the 20th century, was the first scholar to think directly in terms of the social network. His essays point to the nature of network size and the likelihood of interaction in branched networks.

This issue of INTER DISCIPLINA is dedicated to social structures. The element that unites the collaborations presented in its dossier is a vindication of the structuralist perspective in the study of social phenomena. Covering a wide spectrum of phenomena, the contributions of this number look at the phenomena of the labor market, educational processes, on the evolution and determination of inequality and poverty, among others. The expert use of the modern theory of complex networks in some of the articles is remarkable.

The works that appear in the Independent Communications section are related on this occasion to violence against migrants and certain racial identity phenomena in the United States in the second half of the 19th and early 20th centuries.

The interviews and book reviews ratify the Latin American dimension of this issue of the journal: in the pages that follow you can read interviews with prominent Latin American experts (one of them in connection with the works in the dossier) and the reviews of a couple of works on democracy published in Mexico by the UNAM and in Argentina by the Ariel publishing house.