Niklas Luhmann (1927–1998) was a German sociologist and a prominent figure in systems theory, specifically autopoietic systems theory. His work covers various topics, including law, economy, politics, art, religion, ecology, mass media, and love. His most famous work is “Social Systems” (1984), which outlines his theory that society is composed of numerous systems, each operating with a high degree of autonomy from one another.