Michael's Hospital in Toronto and Keenan Endowed Chair and Professor of Surgery in the Division of Surgery at the University of Toronto, Toronto, Ontario, Canada. His professional career has been dedicated to the treatment of patients with brain aneurysms and blood vessel diseases. While he appreciates the progress in the treatment of ruptured brain aneurysms, he believes more scientific work needs to be done to understand why aneurysms form and rupture, and how to improve the outcome of patients who suffer from a ruptured brain aneurysm.