This booklet points out an important principle regarding the knowledge of truth and applies it to the development of Christianity, its various denominations, teachings and practices. This principle is derived from events recorded in the history of human civilization. It is a fact that truth in any field is discovered as a result of careful and unprejudiced scientific inquiry based on logical reasoning and that ideas considered true for a long time by the majority of people need not be really so just because of their age old and unquestioned acceptance. When we examine the Christian church in the light of this principle, we find that many of the doctrines and practices considered sacred by the church today are not in keeping with the teachings of Christ and His disciples, which are recorded in the New Testament. The most important apostolic teachings as recorded in the Bible translated into Malayalam and published by the Pastoral Orientation Centre of the Roman Catholic Church at Kochi, Kerala, India, are pointed out in this booklet and they are contrasted with the present day teachings of the church. The reader finds that there are glaring differences between apostolic teachings and those of the church today. For example, according to the apostolic teaching about forgiveness of sins and Christian baptism, when a person sincerely believes that Jesus Christ died on the cross suffering on his behalf the penalty of his sins he gets his sins forgiven. When he is thus liberated from his bondage to Satan and Jesus becomes his Lord, he feels the desire to obey the commandments of Jesus. And he obeys the first commandment of baptism, which is the outward visible manifestation of the inward invisible spiritual experience he has undergone. He gets baptized in the name of the Father, the Son and the Holy Spirit by being immersed in water and then rising out of it. The immersion symbolizes the spiritual experience of dying and being buried through Christ by faith and the rising out of water symbolizes gaining victory over death and attaining everlasting life through Christ. But the teaching of the Roman catholic church is that forgiveness of sins is gained by baptism and that this ceremony does not need immersion in water and coming out of it, but needs only letting a few drops of water fall on the body. While the apostolic teaching was that faith must precede baptism the Roman Catholic teaching is that it is baptism that must precede everything else. Several other doctrines of the first century church are referred to in this booklet and they are compared and contrasted with the teachings of the Roman Catholic Church, the followers of which form the majority of Christians in the world. With regard to several doctrines and customs, the truth is that what the majority considers Biblical is in fact unbiblical. Careful and unprejudiced examination of church history and in - depth - analysis of various scripture texts lead us to the conclusion that many of the doctrines and practices considered scriptural and apostolic by the majority of Christians are in fact unscriptural and un apostolic. In the light of this fact the most important doctrinal truths recorded in the New Testament of the Bible are mentioned briefly and the readers are advised to make further inquiry with a view to studying and understanding the word of God in the true perspective. In conclusion it is pointed out that the discovery and acceptance of scriptural truths is of eternal significance as it is the factor that determines where a man will spend his eternity- with God in heaven or with Satan in hell.