Living and Proclaiming the Joy of the Gospel This department begins with a series focused on the insights of St. Teresa of Avila into the joy and desire to evangelize which comes from communion with God. In this first article, the author shows how St. Teresa was a woman of deep joy, who was responsive to her profound desire for God, which was a divine gift in itself. 2015 is the five-hundredth anniversary of the birth of St. Teresa of Avila.[1] This is a time of thanksgiving for the whole Church because St. Teresa, as a doctor of the Church, is a light for all the baptized. She is often called “mater spiritualium,” mother of interior souls, because her teaching is about the richness of baptismal life. She was so grateful to the Lord for giving such treasures to souls, whenever he finds them open to his love. “The joy is so excessive the soul (…) wants to tell everyone about it.”[2] I chose this sentence from the Interior Castle as the theme for this series because it is typical of Teresa’s personality. She was a joyful person, always ready to praise the Lord. Where did this joy originate? That is what we will investigate in this series. And, there is another point which is particularly inspiring for the period we are living now in the Church: Teresa was eager to share this joy.