Not long ago, doctors started a fieldwork in the area of sexology, and there are very few of them who adventure themselves in this field and write about what they know. Among them, only a smaller number choose the delicate subject that Doctor Celso Marzano has chosen. Only after years of clinical work and with confidence on his work and on himself is that he chose to write about this human behavior matter. It's already been written that we, Brazilians, because of the importance that we give to this subject, are sodomites. If we are or not, there is no doubt: we are. The question isn't even if we are more or less than other people. The question is that, in order to be a sodomite, we need to act wisely. And in this book we have an analysis, a guide, not with recipes and hygiene advices, but with a new light upon the secrets of the myth that surrounds anal sex. Being impartial when it comes to delicate issues can challenge creativity and maturity. And reading this book, the reader will observe that the author owns both characteristics. And that's rare among the elite that we have described at the beginning of this preface. Taking responsible information, free of prejudice to those who are interested in the subject is not an easy task. People who are dedicated to sexology know how intensely this matter moves in society. Some religions used anal sex practice as an example of typical sinful human behavior. Feminists dressed it as the ultimate proof of the desire that sexists have for humiliating women. This book studies the subject through the eyes of a constructive and guided sexology, not losing sight that the future will give this practice the destiny that the past wasn't bold enough to foresee. In spite of this future, we have here a study that deserves to be read and analyzed as a new challenge to conquer over prejudices and make people aware of the motivations and consequences of sodomy. Md. Eliezer Berenst