Sentence:  Mr Roger Opie, a Cornish farmer whose military knowledge would make him a formidable adversary if ever the Duchy declared itself independent, was the reader for whom I first imagined myself to be writing; to his encouragement, his wife Sue added the photographic expertise which contrived the flattering portrait that adorns the <WSD>backwing</WSD> of the jacket. 
Meaning of the word marked with <WSD> tags:  The flap of a dust jacket that folds around the back cover of a book.