Winner of a 2009 Shingo Research and Professional Publication Prize. Notably flexible and brief, the A3 report has proven to be a key tool In Toyota's successful move toward organizational efficiency, effectiveness, and improvement, especially within its engineering and R D organizations. The power of the A3 report, however, derives not from the report itself, but rather from the development of the culture and mindset required for the implementation of the A3 system. In Understanding A3 Thinking, the authors first show that the A3 report is an effective tool when it is implemented in conjunction with a PDCA-based management philosophy. Toyota views A3 Reports as just one piece in their PDCA management approach. Second, the authors show that the process leading to the development and management of A3 reports is at least as important as the reports themselves, because of the deep learning and professional development that occurs in the process. And finally, the authors provide a number of examples as well as some very practical advice on how to write and review A3 reports.