The Voyage of the Dawn Treader by C. S. Lewis
Practical Mysticism by Evelyn Underhill
Mystical Hope by Cynthia Bourgeault
Gift From the Sea by Anne Morrow Lindbergh
Hind’s Feet on High Places by Hannah Hurnard
Ones I've read are in bold print. The one I haven't read is the only one with an author still living.