The Early Papacy to the Synod of Chalcedon in 451 by Adrian Fortescue is now in it’s fourth edition. The fourth edition came out from Ignatius Press in 2008 and is edited by Alcuin Reid. I picked up the slender volume at the bookstore the other day and was hooked after a few pages. Prior to reading this book, my feeling was that Ronald Knox in his The Belief of Catholics did the best job (as far as my knowledge of apologetic literature goes) of presenting the Catholic case vis-a-vis a moderate protestant position. Now, if I have to recommend a book to an inquiring and serious protestant, it will probably be this volume by Fortescue.
The work originated as a series of articles which appeared in The Tablet in 1919. Fortescue revised them and published them as a book in 1920. The purpose of the articles was to answer the protestants who say that the “Church” to which they owe allegiance (to which we all owe allegiance) is that Church which existed up until some time shortly after 451. Anything that was said or done by the “Catholic” guys at that date and earlier is a-okay. As a corollary, these protestants deny that the modern papacy is anything like (in the relevant Vatican I terms) the papacy at and before 451. Back then, so they claim, the pope was only one of many bishops, even though somewhat more preeminent.

St. Louis-Marie de Montfort,
Pope St. Pius X,
St. Joseph,
St. Ambrose of Milan,
St. Thomas Aquinas,
St. Francis (and St. Clare),
St. Catherine of Siena,
St. Alphonsus Ligouri,
St. John Chrysostom,