Focusing on Billy Prior, The Eye in the Door continues beyond the claustrophobic confines of the Craiglockhart War Hospital, and into a time where Billy and Seigfried have passed their medical boards and been sent, respectively, to the Ministry of Munitions Intelligence Unit, and to the fighting in France. Both Billy and Seigfried are convinced that they are cured, but both are carrying additional mental and physical weights, which threaten to overwhelm and destroy. Barker's writing is, again, both compassionate and brutal, describing in detail the reactions of the men to their descent into breakdown. Some characters are reprised from Regeneration, and new ones introduced. This series is not for the faint-hearted - war is cruel, and Barker describes the cruelty in stark detail. And having lived with a returned service member with PTSD for many years now, I can safely say that both the after-effects of war and the methods by which they are identified and treated have changed very little in 100 years. An indictment on both the armed forces and society.