A co-operative system is a collection of dynamical objects, which communicate and co-operate in order to achieve a common or shared objective. The co-operation of entities is achieved through communication; either explicitly by message passing, or implicitly via observation of another entities’ state. As in natural systems, cooperation may assume a hierarchical form and the control processes may be distributed or decentralized. Due to the dynamic nature of individuals and the interaction between them, the problems associated with co-operative systems typically involve many uncertainties. Moreover, in many cases co-operative systems are required to operate in a noisy or hazardous environment, which creates special challenges for designing the control process. Considerable progress has been observed in all aspects regarding the study of co-operative systems including modeling of co-operative systems, resource allocation, discrete event driven dynamical control, continuous and hybrid dynamical control, and theory of the interaction of information, control, and hierarchy. Solution methods have been proposed using control and optimization approaches, emergent rule based techniques, game theoretic and team theoretic approaches. Measures of performance have been suggested that include the effects of hierarchies and information structures on solutions, performance bounds, concepts of convergence and stability, and problem complexity. These and other topics were discusses at the Second Annual Conference on Cooperative Control and Optimization in Gainesville, Florida. Refereed papers written by selected conference participants from the conference are gathered in this volume, which presents problem models; theoretical results; and algorithms for various aspects of co-operative control.