Nancy Krulik 
Get a Hold of Your Elf! 

Magic School Bus meets the Magic Tree House in this fourth installment of a school-based chapter book series by bestselling author Nancy Krulik. When their teacher takes them to Iceland, can the class escape the trolls?Mr. Frogbottom’s class is on a field trip to Iceland, the Land of Fire and Ice, where the kids meet terrifying and sneaky trolls. But can they find their way back home after the Magic Map goes missing? Bestselling and beloved author Nancy Krulik ingeniously approaches geography in a new way, as the kids learn about the places they visit while fighting, fleeing, or in some cases rescuing monsters.