"Francisco de Osuna: The Third Spiritual Alphabet" by Mary Giles is a book in the Classics of Western Spirituality Series, published by Paulist Press in 1981. This trade paperback edition is 648 pages long and written in English. The book delves into the topics of mysticism and Christianity, specifically Catholicism, making it a valuable resource for those interested in the spiritual practices of the past. With its detailed exploration of the spiritual teachings of Francisco de Osuna, this book offers readers a deeper understanding of the mystical journey in the Christian tradition.