AbstractAfter describing machine and complex adaptive systems (CASs), we definethinking systemas a CAS with two additional, unique characteristics: (1) having goal(s) separate from survival, and (2) having the capability to structure its own learning and to innovate purposefully. Thinking systemsalwayslearn. Healthcare can be considered a paradigm of the thinking system and is repeatedly plagued with unintended, adverse outcomes, particularly fixes that fail. Systems thinking can dissolve such dysfunction in healthcare and by extension in any thinking system. Specific recommendations follow from this rationale. Copyright © 2007 John Wiley & Sons, Ltd.