Yuri P. Kalmykov is Professor of Physics at the Université de Perpignan Via Domitia, France. Professor Kalmykov received his MSc and PhD degrees in physics from the Moscow University of Physics and Technology in 1978 and 1981, respectively. From 1981 to 1998 Professor Kalmykov was a member of the research staff at the Institute of Radio Engineering and Electronics of the Russian Academy of Sciences (Moscow). In 1998 he joined the physics department at the Université de Perpignan Via Domitia, where now he is Head of Division of the research laboratory EA 4217. He has been a visiting academic at Trinity College Dublin for many years as well as being Visiting Professor at the Queens University of Belfast and the Dublin Institute for Advanced Studies. Professor Kalmykov has published over 300 papers, reviews, book chapters and is a co-author of the highly acclaimed research monograph "The Langevin equation" published by World Scientific, Singapore. He is a Fellow of the Institute of Physics, Honorary Fellow of Trinity College Dublin and has received several research awards including the Honorary Diploma of the Russian Academy of Sciences. His scientific activity has a major theme the study of nonlinear and linear responses in dielectric and magnetic relaxation in gases liquids and solids and related physical phenomena. Key words giving an overview of his contributions to research in this area are the following: Brownian motion (classical, quantum, fractional), Langevin and Fokker-Planck equations; random processes; Wigner representation of quantum mechanics, quantum master equations in phase space, dielectric relaxation and absorption in dielectric liquids, gases and liquid crystals; magnetic relaxation of ferrofluids, nanoparticles and spin systems; molecular spectroscopy; Josephson effect; Kerr effect; etc.