In 1917, Siegfried Sassoon—poet, friend of the celebrated Bloomsbury circle, and decorated military hero—had a crisis of conscience about the war he was fighting and penned a letter of protest that was sent to Parliament and published in The Times of London. For this very public refusal to fight he might have been court-martialed, but was instead sent to Craiglockhart War Hospital, in Scotland, to be treated for “shell shock.” Sassoon’s months there have been brilliantly imagined by Pat Barker in her award-winning Regeneration Trilogy. In these meticulously researched novels, as in life, Sassoon is surrounded by genuine shell shock victims—men who have variously lost the ability to sleep, eat, or speak. In The Eye in the Door the trilogy’s central figure, Dr. Rivers, has the increasingly troubling job of “fixing” these men so they can be sent back to the trenches for more of the infernal combat that broke them. If not mightier than the savage sword that inflicted the wounds of World War I, the pen, in Barker’s hand, bears powerful witness to the scars it left behind.