Note: none of these are compulsory. They will, however, help in getting a feel of the world and the morality therein.
Glen Cook - the Black Company series. I own Chronicles of the Black Company and The Books of the South. Anyone willing to loan me the Books of Glittering Stone may well find himself getting extra plot hooks and more bennies, because a happy GM is a generous GM. For the same reason, craft beers are always welcome.
Stan Nicholls - Orcs
China Mieville - Perdido Street Station and the Scar
