Tome of Alteration

This ancient book keeps the secrets to achieve
great arcane power. 20 days (8 hours per day) to
read tome. Arcana Check (DC 1) to see if day of reading was successful. DC is increased by 1 after successful day of reading. Upon completion,
reader gains following benefits: Max. 8 charges.
User gains ability to cast spell (they know), using
as many arcane charges as spell's level without expending spell slot. Can also cast following:
Alter Self (0 charg.) and Disguise Self (0 charg.)