Abstract: The study of radiation processes in celestial objects is a fundamental problem in astrophysics. A powerful tool for the solution of this problem is provided by the theory of radiative transfer. One of the founding fathers of modern radiative transfer theory was the prominent full member of the Russian (formerly Soviet) Academy of Sciences Viktor Viktorovich Sobolev.Academician Sobolev was born on 2 September 1915. All his professional life was associated with the Saint Petersburg (formerly Le…