The book "Treatise on the Principles of Human Knowledge" is one of the most famous works of the English philosopher George Berkeley. In this work, he expresses his fundamental idea that there is only what is perceived by our sensations and experiences. Berkeley refutes the idea of a material world, denying the physical world that exists independently of perception. He develops the concept according to which objects exist only at the moment of perception and consciousness of the individual. "Treatise on the Principles of Human Knowledge" remains a relevant philosophical work that encourages readers to rethink their understanding of reality and existence.