Systems theory is the
interdisciplinary study of
systems in general, with the goal of discovering
patterns and elucidating principles that can be discerned from, and applied to, all types of systems at all nesting levels in all fields of research. Systems theory can reasonably be considered a specialization of
systems thinking or as the goal output of
systems science and
systems engineering, with an emphasis on generality useful across a broad range of systems (versus the particular models of individual fields).