Here, There Be Dragons is by James A. Owen. The first book in The Chronicles of the Imaginarium Geographica series. The Imaginarium Geographica is an atlas of all the lands that have ever existed in myth, legend, fable, or fairy tales. When the old caretaker is murdered by servants of the Winter King, John and his two friends are drawn into a battle in another world to protect the Earth they know and the one they have just discovered from the evil Winter King. A fascinating bit of fantasy with names from history and literature thrown in for good measure.
Ratings: 7th grade - 9 out of 10.