City of Ghosts
What it's about: "Ever since Cass almost drowned (okay, she did drown, but she doesn't like to think about it), she can pull back the Veil that separates the living from the dead . . . and enter the world of spirits. Her best friend is even a ghost. So things are already pretty strange. But they're about to get much stranger."
Ages it's aimed at: 9-12 years
City of Ghosts by Victoria Schwab ($13, originally $18)