Source: Tasha's Cauldron of Everything

Wondrous item, rare (requires attunement by a wizard)

This leather-bound spellbook is reinforced with iron and silver fittings and an iron lock (DC 20 to open). As an action, you can touch the book's cover and cause it to lock as if you cast Arcane Lock on it. When found, the book contains the following spells: Arcane Lock, Dispel Magic, Globe of Invulnerability, Glyph of Warding, Mordenkainen's Private Sanctum, Protection from Evil and Good, and Symbol. It functions as a spellbook for you.

While you are holding the book, you can use it as a spellcasting focus for your wizard spells.

The book has 3 charges, and it regains 1d3 expended charges daily at dawn. You can use the charges in the following ways while holding it:

  • If you spend 1 minute studying the book, you can expend 1 charge to replace one of your prepared wizard spells with a different spell in the book. The new spell must be of the abjuration school.
  • When you cast an abjuration spell, you can expend 1 charge to grant a creature you can see within 30 feet of you 2d10 temporary hit points.