Jesus is the master of the twelve apostles, but Peter was the leader between the twelve. Their mission was to bring the gospel to their Jewish brothers. The Holy Spirit gave all of them the power to heal the sick, cast out demons and even on a few occasions raise the dead. Sorry, I failed to respond to your question sooner.
I'd also like to add that the Apostle Paul was the apostle who enlightened the gentiles about the good news (the gospel). In my humble opinion, I think he was the greatest apostle because, he brought more people to Christ than any of the others.
Paul wrote several books that are part of the "New Testament" (bible). For example, Galations, Colossians and Romans are three of the books. I think altogether he wrote nine of the books in the new testament.
I hope that someday you'll find the time to read them.