Book of John is also the name of a person, John.

Just as a coin has two sides, both valid, so Jesus Christ has two natures, both valid. Luke presents Christ in His humanity as the Son of Man; John portrays Him in His deity as the Son of God. John's purpose is crystal clear; to set forth Christ in His deity in order to spark believing faith in his readers. John's gospel is topical, not primarily chronological, and it revolves around seven miracles and seven "I am" statements of Christ.