In a culture intrigued by various forms of "spirituality," this study invites readers to explore the deep, historically rooted resources of the Christian spiritual classics. It is an invitation to seek the transformative presence of God - the kingdom of God within our hearts - through the spiritual classics. These classics, formed in the matrix of meditation on Scripture, are like road maps that provide invaluable wisdom and guidance for the spiritual journey. Illustrating the importance of theologically grounded spirituality, A Luminous Life draws from Catholic, Orthodox, and Protestant classics that stem from rich trinitarian and christological reflection. This book explores key themes in the spiritual classics, including biblical images and historical models of spiritual development, prayer, fasting, solitude and community, the cross and suffering, the desert, spiritual direction, and contemplation and action. This study seeks to bridge the academic and ecclesial, demonstrating that the life of the mind and life in the Spirit are unified, that theological reflection and spiritual formation go together. Considering exemplary writings from diverse traditions, such as the Desert Fathers, Maximus the Confessor, Teresa of Avila, and John Calvin, A Luminous Life draws readers into worshipful reflection on God and formation in Christ. The book concludes with the encouragement to ongoing, prayerful study of the spiritual classics: as fuel for the luminous life.