The Puritans have been depicted as killjoys whose teachings on assurance of salvation and self-examination bred anxiety and despair. But is that really the case? In The Foundation of Joy, Jeff Strickland investigates the link between John Flavel's understanding of assurance and his pursuit of joy. After explaining Flavel's approach to assurance and how it actually provides a foundation for joy, Strickland demonstrates how Flavel expresses these in the key areas of looking to Christ, discerning the Spirit, obeying the law, keeping the heart, and carrying the cross. Joy is the hallmark of Flavel's spirituality, a fine example of what it means to cultivate a cheerfulness of heart founded on a sense of one's interest in Christ.