Everything is said by an observer, Humberto Maturana (1987) tells us. In this collection of articles, I have invited one set of “observers” to tell us more about themselves. I have asked them to tell us who they are, why they went down the particular roads they chose and have become identified with, what they found, and how and what they have observed. The observers are all scholars who have, to a greater or lesser extent, expressed an interest in and drawn on systems and complexity theories. As we can see from the rich variety of their articles, they interpret these theories in different ways, emphasizing different aspects in different contexts and disciplines, exploring different issues.