In this unique work, Ahmad Al-Ahuwani guides us through three different worlds that constitute the roots of human thought and the paths along which it develops. The journey begins with Greek philosophy, where we encounter the ideas of Orpheus, Aristophanes, Plato, Timaeus, and Aristotle. These thinkers laid the foundations for rational contemplation and the construction of a philosophical methodology. Then, we move onto the world of Islamic philosophy, exploring its major issues: the relationship between reason and religion, faith and disbelief, causality and choice, the concept of “Tashawwuf,” analogies and embodiment, as well as the theories of knowledge among Muslim philosophers. The book also discusses the contributions of Al-Farabi, Al-Ghazali, and Ibn Sina, and analyzes the debate over causality between Al-Ghazali and Ibn Rushd. The third part delves into modern philosophy, exploring the life and philosophy of David Hume, as well as the development of the theory of beauty in Western thought. “In the World of Philosophy” is a book that offers a comprehensive journey through the ages, combining a clear and scientific presentation with deep insights, thereby providing readers with a rich understanding of the foundations of various philosophical schools.