The most honorable thing a person learns. It is the most important thing for a person to learn and teach others about faith, its pillars and requirements. If he is aware of these two serious matters, he will know the path of his happiness, so he adheres to it and does not deviate from it, and the path of his misery, so he avoids it. This book is a study that clarifies the matters of faith and its pillars, and the features of disbelief, its causes, and its entrances.