Catholic Apologetics International
Defending the Historic Catholic Faith
Providing scholarly research and resources to defend and explain the authentic teachings of the Catholic Church through rigorous theological and scientific inquiry.
Popular Books & Films
Explore Dr. Sungenis' most impactful theological works and groundbreaking documentaries
Theological Works
Not By Faith Alone
The Biblical Evidence for Justification
A comprehensive 740-page examination of the Catholic doctrine of justification, providing definitive answers to Protestant objections.
Not By Scripture Alone
A Catholic Critique of Sola Scriptura
A 750-page defense of Sacred Tradition and the Magisterium's role in interpreting Scripture, demonstrating the biblical basis for Church authority.
Galileo Was Wrong
The Church Was Right (3 Volumes)
A groundbreaking multi-volume work examining geocentrism from scientific, historical, and theological perspectives.
Documentary Films
The Principle
2014
A groundbreaking documentary that premiered in AMC and Regal theaters, challenging the oldest doctrine of modern cosmology—the Copernican Principle. Features leading scientists and stunning visual effects.
Journey to the Center of the Universe
2019
An exploration of how modern cosmology relates to classical Christian thought, examining the relationship between faith and science through stunning visuals and compelling evidence.
Explore Our Resources
Comprehensive Catholic apologetics, theology, and scholarship at your fingertips
Resources
Access our extensive library of theological articles, apologetics papers, and research documents.
Videos
Watch presentations, debates, and educational content on Catholic doctrine and apologetics.
Science
Explore the intersection of faith and reason through scientific and philosophical inquiry.
Publications
Discover our published works, research papers, and contributions to Catholic scholarship.
Meet Dr. Robert Sungenis
Dr. Robert Sungenis is a renowned Catholic apologist, theologian, and author with advanced degrees in theology and religious studies. With decades of experience defending the Catholic faith, he has written extensively on Scripture, tradition, science, and apologetics.
As the founder and president of Catholic Apologetics International, Dr. Sungenis has dedicated his life to helping Catholics understand and articulate their faith with confidence and clarity.
What People Are Saying
"Dr. Sungenis's work has been invaluable in helping me understand the depth and beauty of Catholic teaching. His scholarship is rigorous, his explanations clear, and his dedication to truth inspiring."
Sean Naughton
Dublin, Ireland
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