"Some years ago, being for many days on a journey without work or books, I thought that it might be a fair time to write down, in fewest words, the reasons for what I believe. The thoughts were written as the crow flies, over wide lands and a long flight, without deviation from the straight line. Much was, therefore, omitted that might be said, but the continuity and coherence of the reasoning were my only aim. They who will do more solidly what I have done so slightly will deserve and receive my thanks. The text remains as it was written. The references have been since added."
The Appendix contains "A Brief History of the Life of Henry Edward Manning" which provides a background on the reasons why Manning became a convert to the Catholic Faith.