The book "Geometry, 9-11. From educational task to creative authorship and . F. Sharygina is not just a textbook, but a real find for everyone who seeks to understand and master the world of geometry more deeply. In it, the author offers a unique approach to the study of the subject, which allows not only to learn the theoretical foundations, but also to develop creative thinking necessary for solving non-standard problems. The main idea of the book is to take the reader beyond the traditional perception of geometry as a boring and monotonous subject. Sharygin masterfully combines educational tasks with creative elements, which makes the learning process fascinating and multifaceted. The reader is immersed in a world of geometric shapes, theorems and proofs, where each new discovery becomes a step towards a deeper understanding of the subject. This book will be interesting not only for students preparing for exams, but also for teachers who are looking for new methods of teaching. It will be an excellent assistant for students studying mathematics at a higher level, as well as for anyone who is interested in mathematics and wants to develop their analytical abilities. The age category of readers varies from 14 years and older, which makes the book available to both schoolchildren and adults who want to refresh their knowledge. The topics that are raised in the book cover a wide range of issues, from the basics of geometry to more complex concepts such as multidimensional shapes and their properties. Sharygin emphasizes the importance of visualization and intuitive understanding of geometric concepts, which allows the reader not only to remember facts, but also to use them meaningfully in practice. The book is full of examples, tasks and exercises that will help to consolidate the material and develop skills in solving non-standard tasks. Style and . F. It is clear and clear.... It uses simple and easy-to-understand explanations, which makes the material easy to perceive. The author also actively applies illustrations and diagrams, which helps to visualize complex ideas. In his works, you can notice the desire to make mathematics lively and interesting, which is especially important in learning. Sharygin is known not only for this book, but also for other works in which he also raises important questions of mathematics and its teaching. His works often become reference books for teachers and students who seek inspiration and new approaches to learning. "Geometry, 9-11. From educational task to creative” is a book that can change your perception of mathematics. It not only teaches to solve problems, but also develops creative thinking, which makes it indispensable for everyone who wants not only to know, but also to understand. If you are looking for a way to make learning geometry fun and productive, this book will be your faithful companion on the way to success.