This fragmentary black book is reputed to descend from the realms of Hyperborea. It contains puzzling guidelines for frightful necromantic rituals and maddening interdimensional travel. The book holds the following spells: semblance of dread*, ectoplasm*, animate dead, speak with dead, emanation of Yoth*, green decay*, yellow sign*, eldritch communion*, create undead, gate, harm, astral projection, and Void rift*. Spells marked with an asterisk (*) can be found in Deep Magic for 5th Edition. At the GM's discretion, the book can contain other spells similarly related to necromancy, madness, or interdimensional travel. If you are attuned to this book, you can use it as a spellbook and as an arcane focus. In addition, while holding the book, you can use a bonus action to cast a necromancy spell that is written in this tome without expending a spell slot or using any verbal or somatic components. Once used, this property of the book can't be used again until the next dawn.