In this book, we have tried to bring together, as far as possible, the rules of decorum inherent in the mosque, and which it behooves all Muslims to respect. However, who says propriety says negative attitudes and behaviors to banish. Indeed, there are Muslims who, out of ignorance, commit many faults even when they are in the house of God, behaving as if they were in some place and not in the mosque, the place where they are, through their prayers and their remembrance of God, the closest to their Lord. There are also many attitudes that Muslims forget to observe before they enter the mosque and after they leave it. Thus to cause harm to the neighbors of the mosque and to give Muslims a bad image, etc.