John Piper is an American theologian, pastor, and author known for his influential work in the field of Christian theology. He served as the pastor of Bethlehem Baptist Church in Minneapolis, Minnesota for over 30 years and founded the Desiring God ministry, which promotes the idea of finding joy in God. Piper has written numerous books, including Desiring God: Meditations of a Christian Hedonist, which emphasizes the importance of delighting in God. He is also known for his preaching and teaching, often focusing on the sovereignty of God and the importance of Scripture in the life of believers.