The Road Less Traveled: A New Psychology of Love, Traditional Values and Spiritual Growth. 1978 by M. Scott Peck, M.D.
Some years ago, I saw a list of books that people most often cited as changing their lives. The top three: The Fountainhead, To Kill A Mockingbird, and The Road Less Traveled. Why is this book "life-changing"? First, Peck addresses eternal problems of the human condition: love, pain, spirit, happiness. Second, he follows up on his descriptive explorations of these topics with practical approaches for realizing virtue and happiness in everyday life. Finally, as a psychiatrist writing for the secular layman, his observations on spirituality are accessible to Christian, Jew, pagan, and atheist alike.