On World Mission Sunday, October 19, 1997, Pope John Paul II declared St. Therese of Lisieux a "Doctor of the Universal Church." This event marked not only the culmination of an unprecedented series of honors bestowed on "the greatest saint of modem times, " as St. Plus X called her, but it also represented a watershed in the evolution of the understanding of this ecclesiastical title bestowed on only 33 saints in the history of the Church. Certainly, at the time of her death in 1897, no one would have guessed that this 24-year-old Carmelite nun, with such a limited education and imperfect literary style, who never wrote a treatise or published an article and who died virtually unknown in an obscure French Carmel, would one day come to be ranked alongside such eminent personalities as St. Augustine and St. Thomas Aquinas. Her selection did not come about in a vacuum, nor did it happen easily. The story behind the title and her reception of it as documented in these pages makes for truly fascinating and thought-provoking reading.