This is a brief epistle on what is incumbent upon a person to know and believe concerning issues of Tawheed (the Oneness of Allah), the principles of the religion, and some issues pertaining to it which were extracted from the books of the four Imams: Imam Abu Hanifah, Imam Malik, Imam Ash-Shafi'i, Imam Ahmad ibn Hanbal, and their followers, may Allah have mercy upon them, who convened on the creed of Ahl-us-Sunnah wa al-Jamaa'ah and did not differ upon it. I have arranged this epistle in the form of questions and answers to facilitate conveying the information and its retention.