Given their flexibility and ability to embrace the fantastic and wondrous, what can't one write about for middle graders and up? LeAnna Herrera of Mysterious Galaxy bookstore queries the limits with authors Jenn Reese (Above World, Mirage), Jessica Brody (Unremembered), James Morris (Skybound), Nancy Holder (Wolf Spring Chronicles), Cecil Castellucci (The Year of the Beasts), and Greg Van Eekhout (The Boy at the End of the World).