Niklas Luhmann (1927–1998) was a German sociologist and a prominent figure in systems theory, specifically autopoietic systems theory, which he himself developed further. He is known for his comprehensive theoretical work on social systems, distinguishing them from psychic systems (consciousness). Luhmann's work covers various topics, including law, economy, politics, art, religion, ecology, mass media, and love. His most famous work is "Social Systems," published in 1984. In this work, he outlines his theory that society is composed of numerous systems, each operating with a high degree of autonomy from one another. His work has had a significant influence on sociological theory and has also been applied in other disciplines.