Proceedings of the Seminar on Functional Analysis . Issue 1", edited by well-known scientists, including M. A. Krasnoselsky is a real treasure for anyone interested in mathematics, especially in the field of functional analysis. This work is a collection of articles and reports prepared by the participants of the seminar, which became a platform for discussing topical issues and new directions in this field of science. Functional analysis is a branch of mathematics that studies functional spaces and linear operators, and its application covers a variety of fields, from quantum mechanics to control theory. The first issue of "Works of the Seminar" contains works that cover both classical and modern aspects of functional analysis, which makes the book interesting for both students and experienced researchers. Readers will be able to delve into topics such as spectral theory, operator theory and their applications, as well as various methods of exploring functional spaces. This book will be especially useful for graduate students, teachers and practicing mathematicians who seek to expand their knowledge and deepen their understanding of functional analysis. Given the level of materials presented, it is also suitable for senior students of mathematical faculties who want to get a deeper understanding of the subject. If you are interested in mathematics, function theory, as well as practical applications of this knowledge, the "Works of the Seminar on Functional Analysis" will become for you a real guide to the world of complex but fascinating ideas. The book is not only