The Constitution contains seven articles. Many people know that the first three define the roles of the Legislative, Executive and Judicial. However, the other four articles are little known by the average citizen. Article 4 lays out certain information as to how the states are to cooperate with each other, how new states gain entrance into the Union and require all new states to have a Republican form of government. Article 5 defines how the Constitution may be amended. Article 6 covers debts, supremacy, and oaths. And Article 7 discusses the requirements for ratification of the Constitution.

More Info: en.wikipedia.org