Tome of XP: Grants the player 1xp for 4 seconds(total of 4xp points/levels)
Tome of XP+: Grants the player 1xp for 10 seconds(total of 10xp points/levels)
Tome of XP++: Grants the player 1xp for 20 seconds(total of 20xp points/levels)
In order to craft these Tomes, you need to gather XP Ore which generates on the Surface in a select few Biomes. The full list of those Biomes are given in the file description.
All new items/entities grant you extra XP, this is a perfect mod if you were looking for more XP!! :D
