Terry Pratchett 
Reaper Man 
(Discworld Novel 11)

»Inside every living person is a dead person waiting to get out.»
Death has been fired by the Auditors of Reality for the heinous crime of developing . . . a personality. Sent to live like everyone else, Death takes a new name and begins working as a farmhand. He»s got the scythe already, after all.
And for humanity, Death is just . . . gone. Which leads to the kind of chaos you always get when an important public service is withdrawn. If Death doesn»t come for you, then what are you supposed to do in the meantime?
You can»t have the undead wandering about like lost souls – there»s no telling what might happen. Particularly when they discover that life really is only for the living . . .
»One taste, and you»ll scour bookstores for more» Daily Mail
Reaper Man is the second book in the Death series, but you can read the Discworld novels in any order.