A reference book about the Book of Shadow series by Miranda Grant. It includes artwork, slight spoilers for the series, never before seen information about the Shadow brothers and the world behind the pages.
Excerpt from the section about summoning circles:
"You also need to say an incantation to activate the summoning spell and call the demon forth. Most demons only need one to two sentences as they cannot resist the call. Stronger demons can require chanting for a long fucking time.The incantation sounds cool because it's in Drazic, but it's basically just telling the demon to get their ass over here and what you'll do if they don't. So talk as much smack as you want, but you better be able to back it up, especially if it gets free as the demon will hear all of this when they're being summoned.
If a demon appears and fancy shit starts happening inside the circle like smoke and fire, don't go ooh and awww. That's them testing the strength of your magic. They are about to fuck your shit up.
Only a handful of people throughout history have managed to summon a demon prince. Only two people -Lou Lesli Black and Maddox Snail Shadow- have managed to summon one and live."