The ? eld of critical care medicine is in the midst of a dramatic change. Technological and s- enti? c advances during the last decade have resulted in a fundamental change in the way we view disease processes, such as sepsis, shock, acute lung injury, and traumatic brain injury. Pediatric intensivists have been both witness to and active participants in bringing about these changes. As the understanding of the pathogenesis of these diseases reaches the cellular and molecular levels, the gap between critical care medicine and molecular biology will disappear. It is imperative that all physicians caring for critically ill children in this new era have a th- ough understanding of the applicability of molecular biology to the care of these patients at the bedside in order to keep up with the rapidly evolving ? eld of critical care medicine. To the same extent, the practice of critical care medicine is in the midst of fundamental change. In keeping with the Institute of Medicine report “Crossing the Quality Chasm,� the care of critically ill and injured children needs to be safe, evidence-based, equitable, ef? cient, timely, and fami- centered [1,2]. In the following pages, these changes in our specialty are discussed in greater scope and detail, offering the reader fresh insight into not only where we came from, but also where we are going as a specialty.