"Gustavo Bueno's book "¿Qué es la filosofía?" ("What is Philosophy?") is a concise introduction to the study and practice of philosophy. The book is divided into two parts: the first part provides an overview of the history of philosophy, from the ancient Greeks to the contemporary era, and the second part focuses on the nature of philosophical inquiry itself. In the book, Bueno argues that philosophy is a rigorous and systematic investigation of fundamental questions about reality, knowledge, and value. He emphasizes the importance of metaphysics, epistemology, and ethics as the three core areas of philosophical inquiry. Bueno's approach to philosophy is deeply rooted in his materialist philosophy, and he emphasizes the role of science in informing philosophical inquiry. He also critiques various philosophical schools and approaches, including idealism, skepticism, and relativism. Overall, "¿Qué es la filosofía?" provides a clear and accessible introduction to the study of philosophy and is a valuable resource for students and general readers interested in exploring philosophical questions and ideas.