This study deals with the theory of nafs in a cosmological, ontological, epistemological and moral framework, thus aims to provide a holistic perspective to the idea of nafs. The fact that studies in different disciplines on the idea of nafs deal with the issue from a single perspective does not allow to evaluate the issue in a systematic integrity. Because examining the subject of human requires drawing a framework that includes all of the “cosmological” dimensions in terms of determining its place in existence, “ontological” dimensions in terms of examining its structural nature, “epistemological” dimensions in terms of revealing the nature and ways of mental processes, and “moral” dimensions in terms of the origin, quality and target of their behaviors. In this direction, our study, in the context of the theory of nafs, seeks answers to the questions a) “where am I and what am I related to”, b) “what am I”, c) “what and how can I know” and d) “what should I do; in other words, it aims at the analysis of human existence. In the first chapter titled “Ontological Context Areas of the Nafs”; a) the “cosmological context” in which the existential position of the nafs is examined in terms of both the theory of emanation and creation, b) the “ontic context” in which the proofs of the existence of the nafs, the analysis of its essence and its manifestations in each type of being are investigated, and c) the “causal relations context” in which the position of the nafs is examined in the context of temperament theories. In the second chapter, titled “Epistemological Context Areas of the Nafs”, the origin of the cognitive abilities of human beings is discussed. The subtitles of this section are a) proving the existence of the nafs through the phenomenon of ‘knowing’, b) means of providing data in the process of obtaining information: “senses/inner and outer senses” and c) “mind/mental stages”. In the third chapter, titled “The Moral Context Fields of the Nafs”, a) the nature of morality, b) the virtue/immorality and nature of man, which corresponds to the bipolar action field, and c) the ego-based action categories are examined. In the first chapter, the works titled Kitāb al-Nafs / Kitāb al-Rûh written on the subject of nafs, in the second chapter, the works titled Fî al-‘Aql, and in the third chapter, the moral works composed in regard to the idea of nafs have been used. Thus, each chapter has been examined in the context of works that constitute the basis for their respective fields, a systematic has been formed based on the determination of the problematics in these works, and efforts have been made not to lose focus. From another point of view, in our study, the idea of nafs has been first discussed on the basis of Islamic Philosophy, and then evaluated in terms of kalamī/theological thought. This is due to the fact that in our tradition of thought, the theory of nafs is systematically included in Islamic Philosophy for the first time. In our study, the argumentative comparison of the idea of nafs in terms of Kalam and Islamic Philosophy has allowed us to see the characteristic structure of both fields through this theory. Another goal of our study is to make a new classification based on the usage areas of the word nafs in the Quran without being influenced by theological, philosophical and mystical discussions. In this direction, in our study, the answers to the following questions were sought, sometimes implicitly and sometimes explicitly: Is there a narrowing or expansion in the lexical meaning of the word nafs? Is the lexical meaning of the word nafs sticked to in tafsir studies? Do philosophical, mystical and theological discussions have an effect on the formation of the thought of the nafs? Is there a difference between philosophical, mystical and theological perspectives in analyzing the issue of nafs? Is the nafs only the subject of ontology? Which areas are related to the thought of the nafs? What is the reason for the characterization of the nafs as an abstract substance or a subtle body? Is it obligatory to give the nafs an identity separate from the body? Are the arguments on this subject sufficient? What do the aspects of the nafs (vegetative, locomotive, rational nafs / appetitive, spirited, rational nafs) in the literature mean? Are there views that do not consider man as a being composed of nafs and body? What is the basis of these views? Is it because he/she has a nafs that makes man different from other living things? How will the idea of the nafs be proved when it is clear that it is impossible for a human to exist, to have knowledge, to act morally without the body? Is it not possible to consider man as a purely material being? If man is a completely material being, how will his mental actions be explained? If man is a purely material being, how will his moral actions be explained? Does defining human in the form of nafs and body on a dualist basis pose a problem in terms of human imagination? What is the view of Mu‘tazilī, Ash‘arī and Maturidī schools on human and nafs? Has there been a change in the approach of these schools to the subject over time? If so, what is the reason for it? Is the human nafs mentioned in the Quran? Is it possible to produce an alternative thought to studies made on the Quran and to the idea of nafs in philosophical and theological literature? As a result of these inquiries, the following conclusions were reached: a) after a certain stage in our history of thought, the almost generally accepted dualist understanding did not stand before us as a necessity, b) this acceptance is not a belief of or result of being a theist, c) on the contrary, evaluations that deal with human in a holistic way formed the basis of our history of thought, but after the translation activities, the dualist view was tried to be reconciled with Islam with the influence of Greek, Indian, Egyptian and Sumerian philosophy, and this affected both the lexical meanings of the word nafs and the works produced on the subject, d) although human existence, in fact, is not identical with the body, it is all of the material and non-material qualities revealed by the body and the organismal integrity of the body. Therefore, it is not necessary for human existence to think of a being separate from the body and different from the body. In this context, nafs emerges as a concept that covers all material and non-material characteristics of human beings, in other words, corresponds to the structural integrity that will make existence “what it is” and e) this approach is supported by both reason, revelation and literature. [ABSTRACT FROM AUTHOR]