If the team that assembled this brief introductory text has done its job, then the reader, arriving at this page, plausibly knows more about concussive brain injury (CBI) than has almost any prior living intelligent organism. He or she also knows that the journey has been extraordinary -- perhaps not in the sense of grand, but surely in the sense of atypical. The editors decided years ago that they had a duty. The foregoing literature comprised an incoherent map. The duty to start from first principles of logic and biology, in so far as the very limited data and our very limited capabilities permitted, was compelling, onerous, and intimidating. Objectivity is impossible, in view of what Kant refers to as the finitude of human consciousness. All we have is the hope that we have done our best. This final chapter is as iconoclastic as the others. We feel no closure. But we have some confidence in having identified a human need. The editors urge readers to eschew the received wisdom, dismiss the lore, and play a role in the solution. The magnitude of the global problem of concussion remains entirely unknown. It may be pretty big. If so, the sooner we kick-start a revolution in the rigor and vigor of discovery, the better.