Reflections XII-XV (Black Notebooks 1939-1941) by Martin Heidegger is a unique and deep collection of personal notes and philosophical reflections that reveals the inner world of one of the most influential thinkers of the 20th century. This book is not just a collection of manuscripts, but a window into Heidegger’s emotional experiences and intellectual searches in the most difficult years of World War II, when the world was on the verge of disaster, and the author himself was looking for answers to fundamental questions of being. The focus of Reflections XII-XV is the internal dialogue of the philosopher with himself, his reflections on the meaning of existence, the nature of time, being and human responsibility. These pages are filled with sincerity and a sincere search for truth, which makes them especially valuable for those who are interested not only in philosophy, but also in personality psychology, inner struggle and spiritual development. Martin Heidegger, known for his concept of "Being and Time", in these notebooks reveals his ideas in the context of personal experiences, which gives his reflections a special intimacy and depth. The book "Reflections XII-XV" is intended for a wide audience - from students and academicians studying existentialism and phenomenology, to lovers of philosophy, looking for answers to questions about the meaning of life and the place of man in the world. It will be of particular interest to those who appreciate the personal diaries and memoirs of great thinkers, because these records show not only Heidegger's intellectual genius, but also his vulnerability, doubts and sincere search for the truth. The age of readers most likely varies from mature students to older adults who are looking for deep reflections and new ideas. The topics raised in Reflections XII-XV are not only philosophical concepts, but also questions of ethics, responsibility, human destiny and the search for spiritual meaning in the face of global upheavals. The time in which these notes were written is an era of crisis, and it is in this context that Heidegger reflects on the role of man, his responsibility for the future and the need to reflect on his place in the world. These reflections make the book especially relevant today, because questions about the meaning of life and responsibility remain eternal. Martin Heidegger's style in Reflections XII-XV is a subtle combination of academic rigor and personal frankness. His language is full of philosophical terms, but at the same time he is not devoid of poetry and emotional saturation. In these records there is a desire for truth, a desire to understand the deep laws of being, which makes the book not only a scientific work, but also a spiritual guide. If you are already familiar with Heidegger's works, such as "Being and Time" or "What is Metaphysics?", "Reflections XII-XV" will open for you new facets of his thinking, will allow you to look at his ideas from a different angle and understand what kind of inner world he was guided in the most difficult years. For those who are just beginning to get acquainted with his philosophy, this book will be a valuable addition, allowing you to feel the personality of a great thinker and understand his inner contradictions and searches. This book is not only a philosophical diary, but also a powerful tool for thinking about yourself and the world around you. It is worth reading to those who are looking for answers to questions about the meaning of life, responsibility to the future and spiritual values. Reflections XII-XV is an invitation to dialogue with oneself, to reflect on what it means to be human in an era of change and uncertainty. Martin Heidegger created not just a collection of notes, but a philosophical manifesto that inspires deep inner search and spiritual development. This book is worthy of the attention of anyone who appreciates sincerity, intellectual depth and philosophical skill. It will be a valuable addition to any library and a source of inspiration for those who seek answers in the labyrinth of the human soul and the world. In Reflections XII-XV, Martin Heidegger left us not only his thoughts, but also his heart, which makes them truly invaluable for all who seek to understand the meaning of existence and find their way in this complex world.