Apologetics and Catholic Doctrine, Part I: Apologetics by Archbishop M. Sheehan is a classic textbook designed to provide a scientific and persuasive defense of Christianity for Catholic schools, aiming to show the rationality of faith in Christ and the Catholic Church through clear arguments, addressing objections, and using historical and testimonial evidence, ultimately leading readers to understand why they should be Catholic. It systematically presents the reasonableness of the Catholic faith, demonstrating that accepting it is a rational act, not a blind one, by proving the Church's divine authority using miracles and reliable human testimony.