You had me at librarian in Hell.
No way could I resist a book that combines two of my favorite things. The main character, Claire, is tough and determined, though not without her own secrets, and her journey through several realms of the afterlife along with a motley crew of demons and other mythological personages (including a muse!) offer an interesting take on damnation and how we get where we deserve to be.
Hackwith's tale is well-paced, fun, and good enough that I'm looking forward to book two in the series.