Eshel Ben-Jacob: A unique individual in the science of collective phenomena

Eshel Ben-Jacob, one of the co-organizers of this meeting on collective behavior and one of the pioneers in the field of collective behavior in biology, passed away suddenly just before we convened. This article presents a brief glimpse of Eshel's life-long path through science, seen from the perspective of a decades long collaboration on many disparate yet ultimately connected topics. The article attempts to convey how the concept of self-organization of complex interacting objects into higher order functional units, as evidenced so wonderfully by Eshel's experiments on bacterial colony formation, provides a unifying theme for the study of collective behavior. Our entire field will miss his unique ability to "let the complex become simple".