Arcanist’s Encyclopedia

Wondrous item, uncommon (requires attunement by a wizard)

This thick leather-bound tome shows signs of wear even when brand new, pages seemingly dog-eared in advance, and in spite of its heft, the pages seem to flip so easily that one might think that they turn on their own. As a bonus action, this 250-page spellbook can be changed into an encyclopedia that contains a library’s worth of information on magical traditions or back into a spellbook. While holding the encyclopedia, you gain advantage on all Intelligence (Arcana) ability checks. Additionally, you can immediately identify a spell as it is being cast. You can use this last ability three times before needing to complete a long rest to reset the charges of this ability.