Cybernetics and systems science as academic domains were founded in the 1940s and 1950s. Cybernetic systems are defined as systems that are complicated, adaptive, and self-regulating. Systems science is a broader domain that encompasses cybernetics and other systems. Systems science theory states that however complex the world may seem, we can organize it into systems. Therefore, we can find general rules that apply to all systems.  Systems theory focuses on the structure of these systems, while cybernetics focuses more on how they work. These two domains are often studied together, as they both focus on information, feedback, and communication.

-Audrey

Source: http://pespmc1.vub.ac.be/CYBSWHAT.html