SPIRITUAL SUBSTANCE: The Heart of Christianity offers classic Catholic spirituality in a contemporary form. This is the first volume in the three book series: "The Heart of Christianity." Following the traditional three stages or ages of the spiritual life, it seeks to lead readers from the beginning to the end of the spiritual journey to holiness and union with God while focusing on what is most essential or substantial in our spiritual walk with Jesus Christ through His life and death, resurrection and ascension, that is to say, from the first conversion up to the transforming union. Not everyone will understand everything in this book, but may everyone who seeks God find something that helps them.