In the early days of Agile, methods such as Extreme Programming advocated for shipping without a QA phase. In fact, they often didn’t have dedicated testers—or even bug-tracking systems. And yet there are stories of these teams producing an order of magnitude fewer defects than normal. What did these teams do, and why did it work? And what role does that leave for QA? In an age where Agile is interpreted to mean “sprints” and “story points,” the technical side of Agile is often forgotten. In this invited talk for the October 2019 Pacific Northwest Software Conference, I spoke about the technical underpinnings of Agile and how they lead to true business agility.