This volume is a detailed and comprehensive study of the philosophical heritage of one of the greatest thinkers of the XVIII century - Immanuel Kant. Kuno Fischer, a prominent German philosopher and historian of philosophy, deeply analyzes Kant's philosophy, revealing key ideas and revolutionary concepts that changed the course of all philosophical thought. Volume 4 covers a wide range of aspects of Kant's teachings, his biography, and the historical context in which his philosophy developed. Contents: The emergence of critical philosophy: Kuno Fischer explains in detail how Kant's philosophy contrasts empiricism and rationalism, which served as the basis for a new critical philosophy in which questions about the nature of knowledge and the boundaries of the human mind played an important role. Critical Philosophy: The author considers how Kant’s philosophy, defining the mind as the main tool of cognition, offers a new look at the relationship between the mind and the sensory perception of the world. Kant's theory of knowledge: Special attention is paid to the Critique of Pure Reason, which presented a revolutionary concept that opened up new horizons in philosophy. Fisher explains how Kant managed to combine empiricism and rationalism, proposing the theory that our perception of the world is built through categorical perception and is mediated by the structure of the mind. Parallels with other philosophical systems: Fisher analyzes the philosophy of Bacon, Locke, Berkeley, Hume, Descartes, Spinoza and Leibniz, highlighting the main differences and connections with the teachings of Kant. Biography of Immanuel Kant: An important part of the book is a detailed account of Kant's life, his background, training, teaching, and personal beliefs, which have influenced his philosophical work. Kant as a teacher and thinker: The influence of the philosopher as a mentor is considered, as well as the role of his work in the development of scientific thinking and philosophy in general.