What are Aristotle's four causes?

Aristotle offers four causes to explain how things come to be. There is the material cause, which literally refers to the stuff that a thing is made from. There is the efficient case, which is the agent that brings something about - so essentially the hammer and nails. There is the formal cause, which is the sort of thing something is - essentially the idea in mind, so the blueprint. Lastly, there is the final cause, which is the goal or purpose.