There are numerous studies on the esoteric sects in Islam. Though in these studies they have been discussed from different respects, none of them draws attention to the place and importance of the theory of shadows (aẓilla) in the esoteric sects. In this article, after the identification of the meaning of the theory of shadows, it has been argued that the concept of shadows has a central role in understanding the esoteric system of thought. In this context, it has been (...) tried to reveal the central effect of the theory of shadows on the basic ideas of esoteric sects. -/- SUMMARY There are numerous studies on the esoteric sects in Islam. Though in these studies they have been discussed from different respects, none of them draws attention to the place and importance of the theory of shadows (aẓilla) in the esoteric sects. In this article, after the identification of the meaning of the theory of shadows, it has been argued that the concept of shadows has a central role in understanding the esoteric system of thought. In this context, it has been tried to reveal the central effect of the theory of shadows on the basic ideas of esoteric sects. The theory of shadows can be defined as the reflection of the shadows or non-material beings, which appear in the divine world, in this world in a material form. The origins of this view go back to the Plato’s theory of ideas that he formulated as ideas and forms and to his allegory of cave that he used to explain this theory. This theory which was formulated and developed by the pre-Islamic various religious and philosophical traditions took an Islamic form through the bāṭinī/esoteric schools. The theory of shadows was first developed by the extremist groups of shiʿa. Though the early classical works referred the theory of shadow to the extremist shiʿas, they do not give any detail thereof. Nevertheless, it is possible to find in some views of theirs and in the esoteric sects such as Ismailites, Nusayrites, Druzes and Yazidites some clues about the character of this theory. In addition, the later works like Kitāb al-Haft wa al- ʾAẓilla directly articulating the theory of shadows were composed. Although the theory of shadows was not mentioned sufficiently in the works produced within the bāṭinī/esoteric circles, it is witnessed that their understandings of religion were based, to a large extent, upon the theory of shadows. The most basic feature of this unnamed understanding is the claim that every being in the divine world has been reflected in this world in a material form. Since the essence of God generally was kept out from the manifestation (tajallī), reflection was not started with his essence. However, the first beings emanating from Almighty Creator brought the divine world into being and that world was reflected to this world in a material form. With this perception, a Gnostic understanding was developed that the material has no reality and the ultimate reality should be sought in the non-material. According to this, the material beings consisting of only reflection of reality are not possible to have an ultimate reality. The only truth is the meaning, inner (bātin) or shadow which reflects to the world in a material form. Naturally what a bāṭinī should do is to seek the non-material ultimate truth hidden behind the material form. The theory of shadows in this point argued compulsorily the distinction of ẓāhir-bātin (outer-inner). Accordingly, ẓāhir consists of a shell or reflection in which hides the truth. The duty one should do is to go beyond the outer meaning of religious text and to get the inner truth hidden behind the outer meaning. The theory of shadows made a dualist view point obligatory, because every being has an inner aspect which includes the truth and an outer respect in which the ultimate truth is reflected in a material form. God has the inner attributes through which the truth appears spiritually and material attributes to which they are reflected. Universe has a dualist character, a spiritual universe consisting of non-material realities and material universe consisting of its reflections. Human beings have a dualist character, a soul belonging to the divine world and a body belonging to this world. Religious texts which were sent for the salvation of mankind also have two aspects, the inner (bāṭin) belonging to the divine world and the outer (ẓāhir) belonging to this world. Since the Bāṭiniyya considered the divine world to be composed of sevenfold and each fold to be a divine being, they sought, as a result of the theory of shadow, to find in the material world the counterparts or reflections of these beings. Even if their names show differences, the bāṭinī/esoteric groups regarded in certain times some figures as the reflections of the divine world in the material world. Divine beings called al-ʿAql al-Kullī (the Universal Intellect), al-Nafs al-Kullī (the Universal Soul), al-Kalima, Sābiq and Tālī were reflected in the world as the material forms like the Prophet Muhammad, Ali, Salman al-Farisī, Miqdāt b. al-Aswad, Ammār b. Yāsir. This understanding resulted in the divinization of some figures in the world, because it was held that through the manifestation these figures differ from the ordinary people, thus having some divine features. These figures gaining a bipolar identity were outwardly human beings, while inwardly regarded as the forms of divine beings reflected in the world. In this point, what the other people should do is to comprehend, with reference to the figures and their forms, the divine truth reflecting them. This approach brought about a religious understanding in which an individual salvation was not possible and some figures were perceived as charismatic leaders. As a result, the religious understanding developed by the Bāṭiniyya schools is under the ultimate influence of the theory of shadows. With reference to this theory, they developed a new understanding of Islam called Esotericism. At the core of this perception lies the theory of shadows and dualism as its inseparable part. In this sense, Esotericism represents a religious understanding developed in this direction and having a wholeness and deepness. In order to understand this religious understanding correctly, the theory of shadows must be taken into consideration and the esoteric texts be read in this direction. This kind of way of reading, in which the outer is seen as the unique reality, fails to realize the duality behind it, will not enable us to comprehend the inner wholeness of Esotericism and cause to see it as a mass of contradictions. (shrink)