Mysticism and Eastern Religions, the fourth volume in the Collected Works and the third on Nightingale's religion, begins with the publication for the first time of Florence Nightingale's Notes on Devotional Authors of the Middle Ages, translations from and comments on the medieval (and some later) mystics who nourished her own life of faith. Next come her annotations of and comments on the Imitation of Christ, a book to which she turned in times of distress. The largest part of the volume consists of her Letters from Egypt, written 1849-50, a significant period in her own intellectual and spiritual development. Here we provide (for the first time) complete publication and include (also for the first time) material preparatory for the trip and reflections on it over the later years. The last section reports Nightingale's correspondence and journal notes on Eastern religions, mainly Hinduism.