Iron cage, a sociological concept introduced by Max Weber, refers to the increased rationalization inherent in social life, particularly in Western capitalist societies. The "iron cage" thus traps individuals in systems based purely on teleological efficiency, rational calculation and control. Weber also described the bureaucratization of social order as "the polar night of icy darkness". 
The original German term is stahlhartes Gehäuse; this was translated into "iron cage", an expression made familiar to English language speakers by Talcott Parsons in his 1958 translation of Weber's The Protestant Ethic and the Spirit of Capitalism. This translation has recently been questioned by certain sociologists and interpreted instead as the "shell as hard as steel".
Weber wrote: "In Baxter’s view the care for external goods should only lie on the shoulders of the 'saint like a light cloak, which can be thrown aside at any moment.' But fate decreed that the cloak should become an iron cage." Weber became concerned with social actions and the subjective meaning that humans attach to their actions and interaction within specific social contexts. He also believed in idealism, which is the belief that we only know things because of the meanings that we apply to them. This led to his interest in power and authority in terms of bureaucracy and rationalization.
Rationalization and bureaucracy::Weber states, “the course of development involves… the bringing in of calculation into the traditional brotherhood, displacing the old religious relationship.” Modern society was becoming characterized by its shift in the motivation of individual behaviors. Social actions were becoming based on efficiency instead of the old types of social actions, which were based on lineage or kinship. Behavior had become dominated by goal-oriented rationality and less by tradition and values. According to Weber, the shift from the old form of mobility in terms of kinship to a new form in terms of a strict set of rules was a direct result of growth in bureaucracy and capitalism.
Effects of bureaucracies::Bureaucracies were distinct from the former feudal system where people were promoted through favoritism and bribes because now there was a set of rules that are clearly defined; there was promotion through seniority and disciplinary control. Weber believes that this influenced modern society and how we operate today, especially politically.
Weber’s characteristics of an ideal bureaucracy: Hierarchy of authority,Impersonality,Written rules of conduct,Promotion based on achievement,Specialized division of labor,Efficiency.
Weber believed that bureaucracies are goal-oriented organizations that are based on rational principles that are used to efficiently reach their goals. However, there are constraints within this bureaucratic system.
Negative effects of bureaucracies
Bureaucracies concentrate large amounts of power in a small number of people and are generally unregulated. Weber believed that those who control these organizations control the quality of our lives as well. Bureaucracies tend to generate oligarchy; which is where a few officials are the political and economic power. Because bureaucracy is a form of organization superior to all others,further bureaucratization and rationalization may be an inescapable fate.
Iron cage of bureaucracy
Because of these aforementioned reasons, there will be an evolution of an iron cage, which will be a technically ordered, rigid, dehumanized society. The iron cage is the one set of rules and laws that we are all subjected and must adhere to. Bureaucracy puts us in an iron cage, which limits individual human freedom and potential instead of a “technological utopia” that should set us free. it's the way of the institution, where we do not have a choice anymore. Once capitalism came about, it was like a machine that you were being pulled into without an alternative option; currently, whether we agree or disagree, if you want to survive you need to have a job and you need to make money.
Laws of Bureaucracies: The official is subject to authority only with respect to their official obligation
Organized in a clearly defined hierarchy of offices,Each office has a clearly defined sphere of competence,The official has a free contractual relationship; free selection,Officials are selected through technical qualification,The official is paid by fixed salaries,The office is the primary occupation of the official,Promotion is based on an achievement which is granted by a the judgment of superiors,The official is subject to strict and systematic discipline within the office.