Stephen Sackur talks to one of Britain's leading brain surgeons, Henry Marsh. Imagine you are a patient about to undergo brain surgery. If it goes well it'll save your life; if it goes wrong you could end up paralysed or dead. Of course you want to believe your surgeon is infallible, a superhero but he's not; he's all too human just like you. That simple truth emerges from the extraordinarily honest writing of Dr Henry Marsh, He's given us rare insight into the mind of the doctor is it reassuring or troubling?