Romans is the first of the Epistles.
After the five Historical Books of the New Testament, the Bible continues with the Epistles. These are letters written to teach and instruct Christian doctrine. The first nine of the Epistles were written by Saint Paul, and the first is called Romans. It was written whilst Paul was in the Greek city of Corinth, around 56 AD, to the Christians in Rome, a place Paul had not yet visited. He writes to introduce himself and asks the people there to pray for him. In addition, Paul uses his letter to talk about righteousness which comes from God.
Romans 1:18-22
"For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness; because that which may be known of God is manifest in them; for God hath shewed it unto them. For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse: because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened. Professing themselves to be wise, they became fools"