Simplify the following text for a Grade 11 native English-speaking person.
Original: John Stephen Piper ( born January 11 , 1946 ) is an evangelical Calvinist Christian preacher and author , currently serving as Pastor for Preaching and Vision of Bethlehem Baptist Church in Minneapolis , Minnesota .
Simplified: John Stephen Piper ( born January 11 , 1946 , Chattanooga , Tennessee ) is a Reformed Baptist theologian , preacher , and author . He is the pastor for preaching of Bethlehem Baptist Church in Minneapolis , Minnesota , and has written many books .