Biblical scholars generally agree that the James who wrote the Bible's Epistle of James was Jesus' half-brother. Religious historians believe that James did not follow Jesus during Jesus' time on Earth, but rather became a believer after Jesus' crucifixion and resurrection.
One of several epistles in the New Testament, the book of James is a letter to the Gentiles that historians believe was written in A.D. 45 to 48. James was one of the church's chief leaders in Jerusalem, and it is thought that he wrote the book of James while there. The book of James puts a focus on practical faith in the actions of mankind.