The book "Architecture of Computer Systems and Assembler" by Gagarin L. G. and Kononova A. and . is an exciting and deep dive into the world of computing technology, which will become an indispensable tool for students, graduate students and anyone interested in the basics of computer architecture and assembly language. This work not only highlights theoretical aspects, but also offers practical examples, which makes it especially valuable for those who want not only to study, but also to apply the knowledge gained in practice. The book begins with the basics, explaining how computing systems work, and gradually delves into details such as processor architecture, working with memory, and the interaction of various system components. The authors, with a wealth of experience in computer science, make complex concepts accessible to understanding. They use clear and concise language, which allows the reader to easily absorb the material, even if he has no prior training in this area. The topics raised in the book cover a wide range of issues, including the working principles of modern processors, architectural paradigms such as RISC and CISC, as well as the basics of assembly language programming. Each section contains many illustrations and examples, which helps to visualize and consolidate the material being studied. This makes the book especially useful for students of technical specialties, as well as for professionals who want to refresh their knowledge or master new technologies. Those who are interested in programming will especially like the section devoted to assembly language. The authors do not just explain the syntax and semantics of the language, but also show how it interacts with hardware. This knowledge is critical for developers working with low-level systems, as well as for those who want to better understand how high-level programming languages work. The book will be interesting not only for students and graduate students, but also for professional programmers, engineers and anyone who wants to deepen their knowledge in the field of computer systems. It will be an excellent addition to the library of any IT specialist, and can also be useful for teachers who want to use it in the educational process. The style of the authors is clear and structured, which makes it easy to follow the course of thought and not lose the thread of the narrative. Gagarin L. G. and Kononov A. and . are known for their scholarly work in computer science and technology, and their expertise is reflected in every page of this book. Their previous work is also noteworthy, and many readers may be familiar with their other publications, such as "Basics of C++ Programming" or "