Mana

This system is a revision of the Spell Points rule of the DMG page 288-289, replacing the restrictive and artificial Spell Slots with a more intuitive Mana Point system. 

Spellcaster Class

Bard, Cleric, Druid, Sorcerer, Wizard
Each Level in a Spellcaster Class gives you a Spellcaster Level. (There is more but this will not show it)