This is a bloody good book.  Literally.  Hansel and Gretel are the main characters, but their story is not confined to just meeting the witch with the candy house in the forest.  Rather, Gidwitz mines the complete collection of the Grimm’s Fairytales and has the brother and sister show up in stories with which younger readers will probably be unfamiliar.  Along the way, heads are cut off, fingers are severed, and people are cooked.  Because of this reason, this book may be too much to handle for younger readers (in fact, the narrator pops in and out warning the reader to keep the younger kids away).   I would definitely recommend A Tale Dark and Grimm to older readers looking for updated fairytales with a lot of blood.  Grades 5+