Patients with aortic dissection are divided into two main groups: those with hypertension and those with syndromes involving hereditary defects of the aortic wall. The common finding in the setting of both Marfan syndrome and hypertension is dilatation of the aorta. The biological events that may lead to dissection are a decrease in the holding power of the internal layer, an increase in blood pressure, or an increase in aortic diameter combined with a decrease in wall thickness. Treatment of established acute type A dissection is still associated with a hospital mortality of greater than 10% and long-term complications from persistent blood flow in the distal false lumen. The main therapeutic challenge is to prevent aortic dissection by screening of aortic root diameter in patients at risk, together with life-long beta-blockade for Marfan patients. In patients with suspected dissection, the preference is for rapid noninvasive diagnosis and early surgical repair to reduce the risk of malperfusion and irreversible organ damage. Results of surgery have improved, with an increasingly conservative approach to repair of the aortic valve with biological glues. Repair is now routinely carried into the aortic arch using improved methods of cerebral protection such as retrograde cerebral perfusion through the superior vena cava. Nevertheless, there remains scope for further innovation in the prevention and treatment of this difficult problem.