Introduction: the three kinds of consultation. What are we talking about? The key to complexity: systems consultation. What seems to be the trouble? Why healthcare is complicated, and will get worse. Theory to practice: principles, guidelines and some rules. Consultation with working groups and organisations. Consultation as teaching and training. Consultation in assessing and managing clinical problems. Consultation as self-management: consulting with oneself. Consulting the client: the patient as specialist. Medicine as art, art as medicine: the humanities in healthcare. Systems consultation and the other side of common sense.