Spirit of Light or Darkness? is intended to help in both learning and teaching the art of discerning spirits. Discernment, like any other art, demands practice, and Jules J. Toner, S.J., presents real and hypothetical cases along with a step–by–step method for approaching them, including proposed solutions. This book is the fruit of many years of study by the author, who also taught courses and directed workshops on Ignatian discernment of spirits. Fr. Toner first presents Ignatius’s rules for the discernment of spirits themselves, along with some explanatory notes. Then he suggests a method for studying the cases, followed by some two dozen of them, with questions for reflection and a set of proposed responses. The cases come from a variety of sources, including Scripture, contemporary accounts by retreat participants, and historical figures including anti–slavery activist John Woolman.