This work is a masterpiece in convincing the nominal Protestant (or nominal Catholic), the vaguely religious person, or the person without any religious inclinations that God really does exist, that His existence matters, and that only knowledge of Him and obedience to Him can lead to answers to the questions that haunt everyone.
Knox discusses "the truths Catholics hold", "the rules Catholics acknowledge", "the strength Catholics receive", and "the ambitions Catholics honour". These truths, rules, strengths, and ambitions were attractive to the book's first readers. They were answers to the ever-present "Why?". These answers will prove equally attractive to today's readers who, after so many decades of failed isms, yearn for understanding and commitment even more than did their grandparents' generation.