See this worth-it and legally free book & ebook:

  • A Defence of Catholic Principles in a Letter to a Protestant Clergyman; to which is added, an Appeal to the Protestant Public, by the Servant of God Rev. Demetrius A. Gallitzin [born Prince Dimitri Dmitrievich Gallitzin, 1770-1840],
    • The text, together same author’s Letter to a Protestant Friend on the Holy Scriptures , is reprinted in the volume The Writings of Demetrius Augustin Gallitzin (Fitzwilliam, NH: Loreto Publications, 2011). The printed book may be purchased on this page of Loreto Publications, and on this page of Sunrise Marian Distribution.
      • [Note: For the support of faithful Catholic publishers, we encourage all readers to purchase the said book. (The Project earns no commission from any such purchase.) Nonetheless, for those who are unable to do so for just reasons, or would like electronic texts, see the following links below.]
    • The ebook of the fourth edition, corrected and enlarged with ther permission of the author (New York: Catholic Publication Society, 1880) may be read online, and is available in pdf, mobi, epub, and other formats, at Internet Archive.
    • An earlier impression of the same edition (New York: Catholic Publication Society, 1837) is available at Google Books and Google Play Books.
    • Another impression of the same edition (Baltimore: Lucas Brothers, 1837) is available at Internet Archive and Google Play Books.
    • The ebook of the third edition (Dublin: D. Wogan, 1823) is available at Google Play Books . [Note: This is a very poorly scanned copy of the third edition].
    • A still earlier edition (Pittsburgh: S. Engles, 1816) is available at Internet Archive.

On the Feast of Holy Martyr Fidelis of Sigmaringen in the Roman Rite. See also the texts and ebooks listed on the Project page Apologetics and those posted under the category Protestantism. For other texts and ebooks, you may access the List of Free eBooks (Arranged by Title), the List of Free eBooks (Grouped by Subject), the List of Worth-It Catholic Books & eBooks, and the main page of the Catholic eBooks Project.