Practical Mysticism is a book written by Evelyn Underhill and first published in 1915. In this book Underhill sets out her belief that spiritual life is part of human nature and as such is available to every human being. Underhill's practical mysticism is secular rather than religious, since "it is a natural human activity. Underhill's book was written at the outbreak of World War I, at a time of "struggle and endurance, practical sacrifices, difficult and long continuous effort" when, she believed, practical mysticism was the activity needed most.