Knowledge books

You can find knowledge books in dungeons and there's 3 types: dodge, air dive and sword block. Once you have a knowledge book, right click it and, depending on the ability, you'll gain its power.

• The dodge ability let's you move quickly from one place to another
• The air dive lets you have more control in the air for example falling faster or slower and if you have an elytra you'll gain more control
• The sword block is that your able to block attacks with your sword if you don't have a shield and this ability doesn't use the ability bar

Also, once you have a ability it gives you an ability bar which gets used if you use an ability and it regenerates over time.