John Piper is a well-known American pastor and author. He is the founder of a ministry called Desiring God is the chancellor of Bethlehem College & Seminary. He has written many books, and his work has influenced many in the 20th and 21st centuries.
No matter what anyone tells you, know this: Christianity isn't a ticket to the good life. If it were, Jesus' disciples would have ruled the world. Instead, most of them were martyred for their faith. If you're tempted to believe that guy on TV when he says that God wants every Christian to be rich, consider the words of Jesus Himself: