havamal93 mentioned “Galdrabókin” (the witchcraft book) to me, so I looked it up a little, and found it’s a 1500’s Icelandic book which was translated by a Swede and republished a few times.
Haxhem (where I found the links to the books) says:
“It’s interesting to read about Swedish folk-magic and the black-arts books are something of the Swedish grimoires [grimoire = magic/curse-book]. The name is somewhat misleading though, they don’t contain black magic in that way but they’re old and somewhat primitive so some ingredients and rituals would be deeply unethical and completely illegal today.”
The easiest-to-read book is in Swedish and has scanned images here. It’s a very short book, only about 30 pages: https://www.kb.se/OT/Svartkonstbok.htm
(Edit 2015: I began a translation of it to Esperanto some while ago but never finished, it’s HILARIOUS. It has stuff like “fill a human bone with pus, tie a string to it and dangle it in a river that flows facing where the person you want to curse with sickness lives…”)
Here is a library search for “black arts book”, they probably have the Icelandic version too if you search with its name: https://katalog1974.raa.se/katalog1974/FullSearch