For nearly 2,000 years, Christian mystics, martyrs, and sages have documented their search for the divine. Their writings have bestowed boundless wisdom upon subsequent generations. But they have also burdened many spiritual seekers. The sheer volume of available material creates a seemingly insurmountable obstacle. Enter the Upper Room Spiritual Classics series, a collection of authoritative texts on Christian spirituality curated for the everyday reader. Designed to introduce 15 spiritual giants and the range of their works, these volumes are a first-rate resource for beginner and expert alike. Evelyn Underhill, a 20th-century British spiritual writer and retreat leader, is widely known for her compelling exploration of the spiritual life. Underhill offers profoundly simply advice on opening ourselves to God. This volume includes a cross-section of her letters and her published retreat and radio talks.