In the English-speaking world, she was one of the most widely read writers on such matters in the first half of the twentieth century. No other book of its type—until the appearance in 1946 of Aldous Huxley's The Perennial Philosophy—met with success to match that of her best-known work, Mysticism, published in 1911.
Underhill's book, Mysticism: A Study of the Nature and Development of Man's Spiritual Consciousness, was published in 1911, and is distinguished by the very qualities which make it inappropriate as a straightforward textbook. The spirit of the book is romantic, engaged, and theoretical rather than historical or scientific. Underhill has little use for theoretical explanations and the traditional religious experience, formal classifications or analysis.
