The article offers a commented translation of the introduction to the treatise "The Face of Faith" (Wajh-i din) written by the Ismaili philosopher of the XI century Nasir Khusraw and an introductory words.  "The Face of Faith" is considered one of the most important works, since it is in it that Nasir Khusraw sets out the foundations of the Ismaili doctrine, resorting to the method of esoteric interpretation of tawil. In the introductory part to the translation, the author of the article examines the scope of the tawil method, its significance for the ethics, ontology and eschatology of Ismailism. In Ismailism, tawil became the main tool in explaining not only texts, but any phenomena of the surrounding world, since an important role in their worldview was played by the concept of the two-part nature of the entire universe, which is not limited only to external manifestations (zahir), but also had a hidden (batin) meaning inaccessible to the profane eye. Man is called to worship God, and, according to Ismaili teaching, his worship has a dual nature: there is worship by action, accessible to everyone, and there is worship by knowledge, that is, worship through knowledge of the hidden meanings of the verses of the Quran and the precepts of Sharia. The treatise "The Face of Faith" is devoted to the esoteric interpretation in the Ismaili way of such issues as fasting, Hajj, alms, Muslim holidays, imamate, the text of the Koran, etc. According to Nasir Khusraw, a true Muslim believer should do everything prescribed by Sharia with understanding, since only in this case will he be rewarded after death. The reader is offered a translation of the glorification at the beginning of the treatise and an introductory word, which explains the reasons that prompted the Ismaili philosopher to take up the pen, the goals of this book and the table of contents, which allows assessing the variety of issues that worried the author.