Regardless of what you believe of the afterlife, isn't it nice to pretend a moment that there is a place where forgotten stories go to be reread and the art that you started and never finished still exists in a lovely wood paneled room? 

The God of Lost Words dances around several (all?) belief systems about death and the afterlife without necessarily committing to any of them, meaning you can recognize some familiar themes within the story but have no guarantee about the direction any of them will take. It makes for a clever and inventive story. 

An attempt to explain the plot without spoiling the previous two books:

Claire is a denizen of Hell's Library - a library of unfinished and unwritten stories that exists in hell's realm, but is not necessarily part of hell. (Imagine them as just renting space.) She works with a motley crew of fantastical peers who keep the library in order and the books repaired. 

As a result of the events of books one and two, hell is now hostile to the library, and Claire and her companions must find a new realm for it before hell succeeds in destroying them all.

Overall, a fun and satisfying mythological adventure with a hint of romance.