Adam Gidwitz has dug into seldom- explored corners of the Grimm Brothers’ oeuvre to extract the bones of “A Tale Dark & Grimm” (Penguin, 192 pages, $16.99), a marvelous reworking of old stories that manages to be fresh, frightening, funny and humane—if not all at the same time. On the assumption that modern children don’t realize how gory fairy tales once were, the author warns: “The land of Grimm can be a harrowing place. But it is worth exploring. For, in life, it is in the darkest zones one finds the brightest beauty and the most luminous wisdom.” After a pause, he adds: “And, of course, the most blood.” The author’s jaunty asides help mitigate the scariness of following two familiar characters, Hansel and Gretel, through the strange terrain of such lesser-known Grimm tales as “Faithful Johannes” and “The Three Golden Hairs.” There’s a great deal of hacking and decapitation in these pages, along with bad parents, indiscreet ravens and a repulsive dragon. In one half-comic, half-heart-stopping chapter, Hansel travels through liquid fire to hell, where he sees the devil dining on “the fingers of sinners, spiced with their guilty tears.” If this sounds too Tarantino-like for readers ages 10 and up, well, for children of delicate sensibilities, it probably is. For the more robust, Mr. Gidwitz has produced a rich adventure filled with sacrifice and daring that makes for an exciting read-aloud.