Old Filth is the nickname for Sir Edward Feathers, a very old judge as the novel opens. His wife has just died and he's remembering his life, beginning as Raj Orphan when his mother died during his birth in Malaysia. He was raised in Wales with other orphans by a vicious foster mother. He eventually became a successful lawyer and judge in Hong Kong, retiring back to an England he doesn't recognize anymore. He's been a proper man of the Imperial Age distinguished by duty and honour and now without his wife, he's just an lonely icon to an earlier era.