"Desiring God" is a Christian book written by John Piper that emphasizes the importance of finding joy in God. Piper argues that true happiness comes from a deep relationship with God, rather than from worldly pleasures. He encourages readers to seek God passionately and to understand that their ultimate satisfaction is found in Him. The book introduces the concept of "Christian hedonism," which suggests that pursuing joy in God is not only acceptable but essential. Piper believes that glorifying God and enjoying Him are interconnected, and that believers should strive to delight in God's presence and goodness in their daily lives.