Karl Marx was a founding father of sociology who studied the impacts of science, technology, and expanding capitalism on society. He introduced concepts like rationalization and the "iron cage" of bureaucracy. According to Weber, bureaucracy involves rigid divisions of labor, chains of command, and hiring based on qualifications. Weber also studied authority, social action, and the sociology of religion. While his works were hugely influential, some criticisms argue he lacked a critical theory and people were confused by some of his concepts like social action. Overall, Weber established sociology as an important field and his ideas remain very significant today.