Arcanoscientist's Tome
Wondrous item, common
This leatherbound tome contains a wealth of knowledge on one specific school of magicks (the DM chooses which school). It serves as both a spellcasting focus and a spellbook for your wizard spells, has a number of spells of the tome's school inscribed in it, and once per day, you can cast a spell of 5th level or lower inscribed in the tome without expending a spell slot if its school of magic matches the tome's.