The two Corinthian books were authored by the Apostle Paul. The books were actually letters that were written to believers in Corinth in order to clarify certain matters of the doctrine and how believers should conduct themselves in a manner that would be pleasing to God.
First Corinthians is the book that contains information regarding how the church should handle matters that deal with sin. The book stresses the importance of believers staying morally upright in the sight of God and man. Second Corinthians deals with issues of generosity, kindness and impartiality and how they are important to all mankind.