Engineering and scientific research workers were greatly needed in Lithuania for technology development, as industry and energy sector began to grow after World War II. In 1945 the technical departments of Kaunas Vytautas Magnus University began to prepare young specialists and among them those in thermal engineering. Among the graduates of 1947 A. Žukauskas alone became Dr. habil., Academician and Professor. Although he stayed to lecture at the then University, he continued to dream of scientific research, and when he saw in a press publication that MEI (Moscow EnergyInstitute) announced admission to doctorship studies, he visited MEI, acquainted himself with research done there and came to know outstanding researchers and creators of those times in thermal physics and power engineering, professors M. Mikheyev, M. Vukalovich and M. Styrikovich. With them he planned his research course and line to which he later dedicated his whole life. In the beginning of the 20th century the similarity theory was created and used in practice, including generalizations of some laws of heat exchange processes. Due to it, investigation results of heat exchange in various systems may be expressed by simple formulas using the similarity criteria which encompass the parameters describing physical properties of fluids at corresponding temperatures. At the end of the 50s such generating criteria were few. Even in the simplest case of cross flow past the cylinder the main results were obtained using thin wire and a cylinder for the flow of air, and laws for water, oil and other flows, including high temperature gas flows, remained unknown.