The book “Fiber Light Envelope Mods and Long-Period Fiber Gratings” is a unique and in-depth study. which attracts the attention of not only specialists in the field of optics and photonics , but also students, Post-graduate students , As well as ,. who is interested in modern information transfer technologies. The team of authors, consisting of recognized experts in their fields, invites readers to immerse themselves in the complex but fascinating world of fiber optics. The focus of the book is on the sheath mods of fiber optic light guides, which play a key role in modern communication systems. Sheath mods are wave functions that arise in fiber light guides and determine how light propagates through optical fibers. The book discusses various aspects of these modes, including their physical properties, ways of generation and application in real systems. The authors seek not only to explain the theoretical foundations, but also to show the practical application of the acquired knowledge in various industries, such as telecommunications, medicine and sensory technologies. Long-period fiber lattices, which are also an important topic of the book, are a structure capable of changing the properties of light passing through the fiber. These lattices are widely used in the creation of sensors that can measure various physical quantities, such as temperature, pressure, and even the chemical composition of the environment. The authors describe in detail the methods of creating such lattices, their characteristics and application possibilities, which makes the book especially valuable for engineers and researchers. The book will be of interest not only to professionals in the field of physics and engineering, but also to students who are just beginning their journey in studying optics. It can be a great tutorial for those who want to deepen their knowledge of fiber optics and its applications. Readers who are passionate about new technologies and want to be aware of the latest achievements in the field of optics will find in this work a lot of useful information. The topics raised in the book cover a wide range of issues, from theoretical foundations to practical applications, making it worthy of attention. The authors emphasize the importance of fiber optics in today's world, where data transmission speed and communication quality are becoming increasingly critical. The book highlights how technologies based on fiber optics can change our perception of information and communication. The style of the authors is distinguished by clarity and accessibility, which makes it easy to assimilate even the most complex concepts. They strive to make the material understandable to a wide audience, avoiding unnecessary scientific terminology, which makes the book attractive to readers with different levels of training. The team of authors includes both experienced scientists and young researchers, which gives the work freshness and relevance. If you are interested in books such as "Fiber Optics: Principles and Practice" D. K. K. Chau, or "Optics and Photonics" P. G. Brown’s Envelope Mods of Fiber Lights and Long-Period Fiber Gratings will be a great addition to your library. This work not only expands the horizons of knowledge, but also inspires new research and discoveries in the field of fiber optics. In conclusion, this book is not just a scientific publication, but a real find for everyone who wants to be at the forefront of technology and understand how modern communication systems work. Do not miss the opportunity to immerse yourself in the world of fiber optics and discover new horizons of knowledge!