How important was Al Capone in the end of prohibiton?

I have a History exam coming up soon, and need some notes which I'll be allowed to take in to the exam to help me through the essay. How Important was Al Capone in bringing about the end of Prohibition? I'm not so good at History and I absolutely hate it. It would be great if you could give me detailed notes about other examples on who was important to the end of prohibition. Thank you, hope you can help!