Although decompressive craniectomy is a surgical procedure that has been with us for the past 100 years, its prognostic value in long-term outcomes remains doubtful and its use is at a crossroads. Three randomized trials and numerous cohorts, along with comparative studies over the past 15 years (as shown in the presented figure) have significantly improved our understanding of this simple surgical procedure. In writing this book, the authors not only tried to present state-of-the-art evidence describing the molecular and cellular cascades discovered during the past 40 years and current critical care management of traumatic brain injury, but also found it very appropriate to consider the views of scientists who have contributed immensely in understanding the pathobiology of severe head injury (Simard and Fiskum). The current values of multimodality monitoring of neurochemical processes (Badjatia, Bullock) and the contribution of maximal medical management through guidelines (Stein, Ullman) help to understand how far research concerning the management of head injury has come. The authors deem it important to present the personal views of leading scientists who have conducted two high impact randomized controlled trials (Cooper, Hutchinson, Servadei and Sahuquillo) and the experiential views of decompressive craniectomy during the Operation Iraqi Freedom and Operation Enduring Freedom campaigns (Rosenfeld, Neal). Joint discussions of ethical views between the next of kin and surgeons as well as the value of informed consent constitute the ultimate objective before proceeding with the surgical procedure (Honeybul). The promise of the future, which hangs on additional imaging biomarkers with higher predictive values is presented in a systematic review (Aarabi) that stresses a clear view of the extent of rostral-caudal injury severity to the functional connectivity network, and the connectome on magnetic resonance imaging before proceeding with decompressive craniectomy in patients with low motor subscores.