In the last few decades an abundance of publications have accumu­ lated on the clinical implications of subarachnoid haemorrhage (SAH) due to aneurysmal rupture. In contrast, until about 6 years ago, SAH due to traumatic head injury mainly, if not only, drew the attention of the forensic pathologist. In their analysis of the data from the American Traumatic Coma Data Bank, Eisenberg et al. concluded in 1990 that the presence of SAH on the initial computed tomographic scan (tSAH) had an un­ favourable effect on outcome. This conclusion has since been con­ firmed in other series. Dr. Kakarieka, the author of the present monograph, has been fascinated by tSAH since his participation in 1989 as International Trial Coordinator of the large European Trial on the effect of nimodipine on outcome after severe injury (HIT 2). This study re­ vealed a statistically significant, favourable effect in the subgroup of patients with tSAH, a result which warranted a further trial on the efficacy of nimodipine administration in patients with tSAH. This trial, the so-called German trial which was completed in 1995, not only revealed that tSAH is an important and independent factor predicting unfavourable outcome in head injury, but also showed convincingly the statistically significant, favourable effect of nimodipine adminis­ tration in patients with tSAH.