Action and Adventure
When her young niece disappears, deep sea submersible pilot Will Roan embarks on the mission of her life. Her journey takes her from the frightening interior landscape of her own untrustworthy mind to the discovery of two parallel worlds locked in a power struggle -- and the outcome depends on her.
The Talisman (and sequel Black House) by Stephen King and Peter Straub
His Dark Materials (trilogy) by Philip Pullman
Neanderthal Parallax (trilogy) by Robert J. Sawyer
