German sociologist Niklas Luhmann (1927-1998) was perhaps the most prominent European sociologist of his time, as well as the author of a prolific list of publications.Luhmann was influenced by his teacher, Talcott Parsons, of functional sociology fame, and by Edmund Husserl's phenomenology. Although functional sociology and phenomenology are seemingly incompatible, Luhmann was able to provide a new twist to the Parsonian legacy, stressing meaning as the driver of the social system.Temporal selectivity is based on the passive-active method. This dimension was borrowed by Husserl's work on passive syntheses. Luhmann was able to achieve a theoretical orientation which was nonhierarchical for 21st-century society. His work is far reaching in its conceptual and comprehensive grasp of accounting for technological modernity and postmodernity within modernity.The essays address the logic in Luhmann's work through concrete investigations of system, environment, and world. These investigations in law, organization, gender, the world of technology, structuration, and race demonstrate some of the breadth of Luhmann's work.