The article concerns the philosophical interpretation of letters in the poems of the great Azerbaijan poet Imaddaddin Nasimi. The study consists of 4 parts. First, the information about “ Khuruf al-Mukatta’ a” from Koran and from ancient wise ideas represented in the themes of poems by Khalladj Mansur and Nasimi has been expounded. A very important point stressed here is that the letters of language, which a person percieves the Truth and communicates with the Creator of Spirit in, also play a role of a key to the Divine Truth. The second part of the article is devoted to the question of what kind of truth is delivered by letters as it is expressed in Nasimi’ s poems. The great poet used the method similar to method used in Holy Koran considering the letters as symbols. The study revealed that the poetry by Nasimi is a proclamation of the Mystery of letters from the beginning up to the end, and the poet is doing that in a logical way, referring to Koran and strictly following the spirit and the letter of Allah and His book. The third part of the article contains the discussion of the letters – Kaf-and – Nun-as being an expression of the process of creation. It is also marked here the fact that the matter is not only about the God but about a Man. Being a vicar of Creator a Man is a Creator too but within the frames and abilities established by the God. If a man was created by the force of Kaf and Nun the word is a creator of him and the meaning for creating of him as well. From this point, there are no limits for word. It can increase and reduce depending on measure of thinking. The last part represents the philosophical interpretation of the famous phrase “ Ana al-Hakk” which was first formulated by Mansur Khaladj and demonstrates a whole depth of Nasimi’ s poetry. This phrase is a manifestation of self-expression of the man who is in unity and harmony with the Creator, and Nasimi’ s poetry is an accumulation of wisdom expressed in this unity.