Praying to Mary, celebrating the Mass, venerating the Pope—you won’t find those doctrines in the Bible. And yet more than one billion Roman Catholics throughout the world follow such practices in line with the official teaching of the Roman Catholic Church.

With that many Catholics around the globe, it’s likely you know some of them as relatives, friends, neighbors, or co-workers. Find out what they don’t know—the origin and error of Catholic doctrine—so you can help the Catholics you know out of the darkness and into the light.