The most recent and relevant paradigm shifts in systemic sociology surround pivotal topics for the social sciences because these shifts played three crucial functions: a) these shifts anticipated a new alliance between hard and soft sciences in the framework of complexity, b) these shifts allowed the autopoietic conception of a system to emerge beyond the rigidities of the oversimplified, old fashioned whole/parts paradigm, c) these shifts, through an increasing abstraction and dematerialization levels clearly explained that "reality", "future", and "trends", are more inventions than descriptions. At the crossroads of these three crucial functions, Niklas Luhmann's (1927-1998) writings are fundamental. Nevertheless this is not a book about Luhmann. Pre-Luhmannian systemic theory is obsolete, Luhmann's last masterpiece Die Geselschaft der Gesellschaft (1997) anticipated the increasing width of the global systemic horizons and the resonant noise from the environment against them. Luhmann's works changed the systemic vision forever.