Italy:
Andrea Camilleri - Inspector Montalbano Series (bestsellers books in Italy and from which was created a very successfull TV series)
Massimo Carlotto - Death's dark abyss
Niccolo Ammaniti - I’m not scared
John Grisham - The broker
Steven Saylor - Roma sub rosa Series
Spain:
Carlos Ruiz Zafon - The shadow of the wind
Carlos Ruiz Zafon - The angel's game
France:
T. A. Chappel - Mask in the corridor
Sweden:
Lars Kepler - The hypnotist
Johan Theorin - The darkest room
Sorry for the long list but when the books are involved I can't resist!