Catarina Benincasa, known to the world as Catherine of Siena, is one of the strangest and most intriguing of the church’s saints. An uneducated woman from an ordinary family, she became, in the course of a very short life, an object of fascination to thousands and a counselor to kings, queens, and Popes. Though she never studied theology and never learned formally to read or write, she came to be recognized as a doctor of the church and a master of the spiritual life. Her mystical connection to the higher world—she spoke to Christ, Mary, and the other saints as casually as one friend talks to another—constitutes a powerful challenge to the flattened out secularism of our time. She witnesses to the deeply biblical truth that the higher world and this world are not separated by a terrible gulf, but rather interact, inter-penetrate.