The Dialogue takes the form of a conversation between God and Saint Catherine of Siena covering four subjects. The treatise on divine providence explains the connection between love and suffering, emphasizing that God wants only our love and the service we give to our neighbors. The treatise on discretion introduces the metaphor of the Bridge from earth to heaven. The treatise on prayer gives instructions for the progress from vocal to mental prayer, and describes the higher degrees of prayer. The treatise on obedience covers the necessity and rewards of obedience. Catherine of Siena was a third order Dominican in fourteenth-century Tuscany. As a young adult, she devoted herself to prayer, fasting, and mortifications. After this period of solitude, with its accompanying ecstatic visions, she went out into the world to care for the sick and the poor. Catherine also worked to bring peace and unity among Christians. She was canonized by Pope Pius II and declared a Doctor of the Church by Pope Paul VI.