I ordered this book (and the rest of the Ever World series) because K.A. Applegate is the same author of the Animorph books, which I ordered for my 9-year old son, who can't read them fast enough! He loves them!
I ended up reading Search for Senna, the first in the series, and the author grabs your attention and keeps it. I finished it in one night. Very interesting. A parallel world with gods of Celtic, Aztec, Egyptian and Norse origin, and 5 humans caught in both worlds.
I highly recommend this book to readers of any age.