The main model that I have been using to guide my research and teaching practice has been that of John Holland, father of genetic algorithms and professor of psychology and computer science & electrical engineering at the University of Michigan. His model of complexity theory (Hidden Order, 1995) considers complex systems to have four properties (aggregation, diversity, flows, and nonlinearity) and three mechanisms (internal models, building blocks, and tags). Most of my work has looked at the networks of knowledge flows and the role of building blocks in learning. If you go to the Complexity and Education website, you can read two of my articles: "The role of networks in learning to write" and "Building blocks and learning." I'll be looking at those two articles over the next few weeks. Comments are welcome.