I would have to go with "Watcher in the Shadows" by Geoffery Household. The grand-daddy of all chase novels, this book takes you on a trip through the English countryside in the early '50s. A mild-mannered ex-Secret Service agent is wrongly targeted and stalked by a concentration camp survivor who blames him for war crimes.

Written in a more refined time, by a true gentleman, this book may only appeal to those of a certain age, which is a pity.