Niklas Luhmann was a German sociologist who studied how people interact with each other and how that affects the way things get done in a society. He wrote a lot of books and articles to explain his theories, which are still studied today by people who want to learn more about how societies work. He thought that most of the decisions people make, and the way different systems interact with each other, can be understood by looking at the communication and interactions between people. In other words, he thought that looking at how people talk to each other can help us better understand the world around us.