The Regeneration Trilogy By Pat Barker

The Regeneration Trilogy (Regeneration; The Eye in the Door; The Ghost Road)
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Regeneration--A sombre, brillant novel ... at its centre is a real-life encounter that occurred at Craiglockhart in 1917 between W.H.R. Rivers, and army psychologist, and Siegfried Sassoon ... Intense and subtle, getting responsively under the skin of both real and imagined characters