From publisher blurb:
This is a gamemaster supplement intended for Deluxe Tunnels & Trolls (although it will work with any version of the rules). Ken St Andre has decided that each of the kindred (Dwarves, Elves, Fairies, Trolls, etc) should have its own spell book, and this is the one for the Gremlins. Gremlin magic is all about naughty thrills and supernatural spite. It can grow warts on your tongue, rot your dinner, and give your favorite milch-goat bad ideas! Gremlin magic isn't evil, but it is BAD, very bad.