Disaster Medicine is a relatively new multidisciplinary field of science with clear public health implications as it focuses on improving outcomes for populations rather than for individual patients. As with any other scientific discipline, the goal of public health and disaster research is to create new knowledge and transfer evidence-based data to improve public health. The phrase “lessons learned” has crept into the disaster lexicon but must be permanently erased as it has no place in the scientific method. The second edition of Koenig and Schultz’s Disaster Medicine: Comprehensive Principles & Practice adds to the growing knowledge base of this emerging specialty and explains why “lessons learned” should be discarded from the associated vocabulary. (Disaster Med Public Health Preparedness. 2017;11:610–611)