Complex adaptive systems (CAS) are a useful way to think about health care and especially across organizations--coalitions. Plsek's Appendix B in the Institute of Medicine’s Chasm Report is the most important part of the book. The challenge of the book is to create a coherent system that will dramatically reduce the burden of illness in the citizens of this nation. Success is impossible without understanding the way complex, adaptive systems work. # Rules for optimizing a CAS: 1. Agreement upon clear aims (patient-centered, safe, equitable, etc.) 2. Follow a few simple rules (cooperation, relationship, transparency, etc.) 3. Ensure effective communication among the agents/parts 4. Provide opportunities and resources for experiments (fertilizing and watering) 5. Pruning (removing resources from experiments that fail to move the system closer to the aims) 6. Explicitly model the system for policy making Robert Wood Johnson Foundation paid for the modeling of Congestive Heart Failure and Diabetes care in Whatcom County. The understanding of the local health care system's dynamics is already helping our key stakeholders to come together and prevent misaligned incentives preventing cooperation. I have never seen anything like this before.