Puzynin Igor Viktorovich 24.04.1938 – 17.07.2023 On 17 July 2023, Advisor to the Directorate of the Meshcheryakov Laboratory of Information Technologies JINR, Professor, Honoured Scientist of the Russian Federation Igor Viktorovich Puzynin passed away. He was a world-famous scientist, who brought up generations of mathematicians and scientists in many JINR Member States. Igor Viktorovich Puzyrinin was born on April 24, 1938 in Voronezh. After graduating from school in 1955, he entered the Faculty of Mechanics and Mathematics of Moscow State University and after graduating in 1960, I.V. Puzyrinin was assigned to the Laboratory of Theoretical Physics of JINR. In 1966, Igor Viktorovich became an employee of the new Laboratory of Computing and Automation of JINR, with which all his further scientific activities are inextricably linked. At JINR, he worked his way up from a senior laboratory assistant with a higher education to the director of the Information Technology Laboratory. In 1969, Igor Viktorovich became a candidate of physical and mathematical sciences, and in 1979 he was awarded the degree of Doctor of Physical and mathematical Sciences for his work "A continuous analogue of Newton's method for numerical solution of quantum mechanics problems". Igor V. Puzynin is a well–known scientist in the field of computational and applied mathematics. He created a new direction "computational physics" at JINR for algorithmic and software support of theoretical and experimental research based on the effective use of modern computing systems and high-speed networks. Under his leadership, JINR has developed a scientific direction for the creation, theoretical justification and practical implementation of computational physics methods for the numerical study of nonlinear multiparametric models of complex physical systems. The most important contribution to this direction is the development of a unified approach for the numerical analysis of boundary and spectral problems for systems of nonlinear multiparametric differential and integro-differential equations based on a generalization of the continuous analogue of Newton's method. Thanks to the development of this approach, a number of important physical results have been obtained in the theory of muon catalysis, the theory of the nucleus, in nonlinear problems of quantum chromodynamics and condensed matter physics. I.V. Puzynin headed the work on mathematical and software support of theoretical calculations according to the Program of research on the phenomenon of muon catalysis, approved by a joint decision of the SCAE and the Presidium of the USSR Academy of Sciences. He was co-director of the general institute topic "Theoretical and experimental studies of the electronuclear method of energy production and transmutation of radioactive waste". Igor Viktorovich until the last day headed the direction for the development of mathematical models and methods, algorithms and programs for the numerical study of processes arising from the irradiation of materials with particle beams. Igor Viktorovich is the author of more than 250 scientific publications. From 1988-2000, as Deputy Director of LVTA for Scientific Work, Igor Viktorovich made a huge contribution to the convergence of the scientific interests of theoretical physicists and experimenters from different JINR laboratories with specialists in numerical analysis and computer processing of experimental information. From 2000 to 2003, Igor Viktorovich was the first director of the Information Technology Laboratory. It was during these years that JINR initiated the development of distributed computing and grid technologies. Since 1998, on the initiative of Igor Viktorovich and under his direct leadership, they have been regularly held. international conferences on modern areas of computational physics. In 2004, Igor Viktorovich was awarded the title of "Honored Scientist of the Russian Federation", he is the author of more than 250 scientific publications, he was awarded the JINR prizes for the best scientific works 5 times. Professor I.V. Puzynin made a great contribution to the training of scientific personnel. Igor Viktorovich was a professor at the Department of General Mathematics and Mathematical Physics Tver State University, Head of the Department of Information Technologies of Computing Systems in Moscow Technical University "Moscow State Institute of Radio Engineering, Electronics and Automation (MIREA)". In 1968-1980 . he taught at the Department of Theoretical Nuclear Physics of the Faculty of Physics of Moscow State University. Igor Viktorovich was an honorary doctor University of Plovdiv, Bulgaria, Honorary Professor Mongolian State University. Under the leadership of I.V. Puzynin, 11 candidate dissertations were defended, 8 of his students became doctors of physical and mathematical sciences. I.V. Puzyrinin was awarded the medal of the Order of Merit for the Fatherland of the II degree, the medals "Veteran of Labor" and "In memory of the 850th anniversary of Moscow", the departmental badge of distinction in the work "Veteran of Nuclear Energy and Industry", Certificates of Honor of the Ministry of Education and Science The Russian Federation, JINR and Dubna, Honorary diplomas of JINR, the medal "50 years of Poland's participation in JINR", the medal "Nairamdal", Mongolia, the Order of the Polar Star, Mongolia, the gold medal of the MAN "Kublai Khan", as well as Honorary titles of universities and awards of a number of JINR member countries. A great man, a talented scientist and Teacher, a wise mentor, a kind and reliable person has disappeared. Igor Viktorovich left a deep mark on science and a bright memory for everyone who worked with him, was friends or just talked. We will all miss his kind humor and wise advice very much. The JINR and LIT Directorates and the Laboratory staff express their sincere condolences to the family and friends of Igor Viktorovich. The bright memory of a wonderful man and a real scientist will always be with us.