It is generally considered that Jovan Karamata is one of the greatest and the most influential Serbian mathematicians in the XX century. His mathematical contributions belong mainly to mathematical analysis, particularly to the Tauberian theory. Probably his most known and most important work is his invention of slowly varying functions. Today, this theory has many applications, particularly in probability theory, but in ordinary differential equations, complex analysis, number theory and even in cosmology as well. In this paper we present a digital collection ofhis books deposited in the Virtual Library of the Faculty of mathematics in Belgrade.