The Fuel and Combustion Laboratory of the University of Belgrade - Faculty of Mechanical Engineering and the Society of Thermal Engineers of Serbia have the great honour and privilege to present this special jubilee issue of Thermal Science on the occa-sion of the 80th birthday of Prof. Milan Radovanović, president of the Society of Thermal Engineers of Serbia, and celebrating his active involvement in science for 54 years. This year he has completed 15 successful years at the helm of and contributing to the develop-ment of the Society of Thermal Engineers of Serbia. Prof. Milan Radovanović contributed significantly to the work and development of the Fuel and Combustion Laboratory, creating new generations of mechanical engineers, opening new fields of research, involving new, young researchers, and establishing cooper-ation with numerous institutions in Serbia and abroad. Due to his dedication, scientific and systematic approach, and relationships with colleagues, he instigated a completely new spir-it in the work of the Laboratory, improving the quality of lectures, scientific research and international cooperation. He offered his colleagues in the Laboratory his non-conditional expert and scientific support, which was always complemented by his strong intellectual and broad cultural knowledge and versatility. This special issue of Thermal Science journal is prepared in cooperation with col-leagues from the University of Twente, Enschede, the Netherlands, where Prof. Radovanov-ić spent several years as a professor and researcher. His work at the University of Twente additionally influenced his understanding of scientific research and the importance of inter-national collaboration. This successful collaboration is continued till today.