The study, entitled "The efforts of the Khalili investigator in interpretation and the science of the Quran through the Book of Preliminary Rules of Faith, collect and study" to put in the hands of scholars and those interested in the science of the Quran a study on the interest of the Sheikh of the detective Said bin Khalfan Al Khalili in the science of the Quran. The research problem in this study that is Al-Khalili’s efforts in interpretation and the sciences of the Qur’an are scattered within the folds of his encyclopedia “Preliminary Rules of Faith” and are not arranged under specific headings that facilitate the student and scholar’s easy access to them. This study came to address that problem by collecting, gathering and studying these efforts from the Encyclopedia “Preliminary Rules of Faith”. This study coming in preface and two chapters. The preface included the introduction of the Khalili investigator and the book The Preface of Faith. Chapter I was entitled "The Khalili investigator's interpretation efforts and approach". The second chapter was entitled "The Efforts of the Khalili Investigator in the Sciences of the Holy Qur’an". The study relied on the inductive approach to extrapolate the encyclopedia Preliminary Rules of Faith, the analytical approach to analyze and study some of the opinions of the investigator Al-Khalili in interpretation and the sciences of the Qur’an, the deductive approach to derive the approach of the investigator Al-Khalili in interpretation and the sciences of the Qur’an, and the comparative approach to compare the opinions and sayings of the investigator Al-Khalili with some of the sayings of the scholars of interpretation and the sciences of the Qur’an. The study concluded with important findings, including: Al-Khalili, the investigator, paid attention to interpretation, and he made significant efforts and contributions to the science of interpretation, even if he did not produce an independent interpretation, his exploration of this science and his interest in the sections of interpretation appeared in his answers to some questions. In the field of interpretation by narration, the investigator Al-Khalili was knowledgeable of the readings, so he relied on them in his interpretation, and the hadiths that were authentic to him, and relied on the sayings of the interpreters among the Companions of the Messenger of God. As for the field of interpretation by opinion, Al-Khalili was careful not to delve into the interpretation of the problem of the Qur’an from the point of view of meaning and left its knowledge to God Almighty out of purity and veneration. In the field of interpretation, it is noted in some of his answers that he excels in this field, as he deals with the topic in all its aspects, explaining, interpreting, and discussing the evidence, and an example of this is the topic of jihad. Al-Khalili, the investigator, was interested in the sciences of the Qur’an, such as abrogation, readings, the rulings on stopping and starting, and the rulings on Tajweed, and this was prominent in the book of Preliminary Rules of Faith. Among his sayings are: that there is no obligatory stopping in the Holy Qur’an, and that it is not permissible to stop on an exception and start with what comes after it, and he believes that the occurrence of Abrogation in the Qur’an, and abrogation occurs in commands and prohibitions and not in the news. As for the science of Tajweed, oral communication is required to learn and master it