This book provides an easy-to-read introduction to the theology and science of natural family planning. It provides a historic overview of the papal encyclicals regarding the traditional Catholic teaching against contraception. The church calls everyone to be holy and chaste. Chastity is simply saving sex for the holy sacrament of marriage between a man and a woman. The book uncovers all the harmful effects of artificial contraception and reveals the truth, beauty, and goodness of NFP. It focuses on the LA study sponsored by the US Department of Health, Education, and Welfare that demonstrated no surprise pregnancies over two years using the symptothermal method. The book provides color charts demonstrating the four main hormones of the female endocrine reproductive system and how each affects the temperature and mucus signs which determine the fertile and infertile times in a woman's cycle. The is a must read for anyone confronted by the progressive, contraceptive-abortive mentality in our society.