We propose a stylized model of a problem-solving organization whose internal communication structure is given by a …xed network. Problems arrive randomly anywhere in this network and must …nd their way to their respective “specialized solvers”by relying on local information alone. The organization handles multiple problems simultaneously. For this reason, the process may be subject to congestion. We provide a characterization of the threshold of collapse of the network and of the stock of floating problems (or average delay) that prevails below that threshold. We build upon this characterization to address a design problem: the determination of what kind of network architecture optimizes performance for any given problem arrival rate. We co...