The title of this commentary on the Heidelberg Catechism takes its inspiration from the catechism’s second question, which asks “What do you need to know in order to live and die in the joy of this comfort?” The comfort referred to is that which is described in the famous first question and answer, the comfort of knowing “that I am not my own, but belong with body and soul, in life and in death, to my faithful Savior Jesus Christ.” The Christian art of living and dying in joy is explored in this guide to the catechism, which focuses on the biblical background and exposition of the grand themes of misery, redemption, and gratitude. This translation is published on the 450th anniversary of the publication of the Heidelberg Catechism as an aid to the devotional reception of this historic and continually relevant symbol of the Reformed faith.