Puritan pastors of the seventeenth century were true physicians of the soul, and this is made readily apparent in Adam Embry’s study of John Flavel. In Keeper of the Great Seal of Heaven, Embry shows the prominent themes of heavenly mindedness and the work of the Holy Spirit in Flavel’s life and pastoral ministry. He goes on to evaluate Flavel’s teachings about the Spirit, explains Flavel’s view on the sealing of the Spirit, and compares Flavel with other Puritans. Embry further traces the significance of Flavel’s theology of the Spirit in the American Great Awakenings, gives an evaluation of Flavel’s exegesis relating to the sealing of the Spirit, and concludes with an insightful pastoral reflection on the material. While this study reveals a diversity of thought within Puritanism, it also underscores the profound commitment this spiritual brotherhood shared for treating the matter of the heart with biblical truth in dependence on the Holy Spirit.