This special issue of the journal Thermal Science is dedicated primarily to recent scientific achievements of the Faculty of Mechanical Engineering, University of Belgrade, and Innovation center of the Faculty of Mechanical Engineering, Belgrade, which has been now active in Research and Development for almost 10 years. This special issue contains 28 papers, mostly based on scientific research performed by professors and doctoral students from the Faculty of Mechanical Engineering, University of Belgrade, and its Innovation center, including 5 doctoral projects of Libyan students, several important contributions in co-operation with the Faculty of Engineering Sciences, University of Kragujevac, and Faculty of Technology and Metallurgy, University of Belgrade, University of Osijek, Croatia, and University of Kosice, Slovakia, as well as papers from Slovenia, Spain, India and Malaysia. Modern experimental, numerical and analytical methods have been presented to solve thermal problem in engineering like temperature, strain and stress distribution in steam turbine components under thermal load, especially boilers, furnaces, casings and steam pipelines. Also important topics like creep and remaining life of thermally and mechanically loaded components have been analyzed, as well as thermo-mechanical processes like welding. It has been demonstrated that even the most complicated engineering problems, including three-dimensional complex geometries and non-linear material behavior, can be successfully treated, providing reliable and precise results for non-stationary temperature and stress fields. Finally, ferromagnetic behavior due to high frequency effects, energy efficiency and HVAC have been also treated as thermal problem. All the papers have been revised according to high standards of the journal Thermal Science which have positioned the journal high on the worldwide SCI list in the area of thermal science. Special gratitude for this goes to Professor Simeon Oka, chief and executive editor of the journal Thermal Science, and professor Milan Radovanović, president of the Society of Thermal Engineers of Serbia. Finally, I am also sincerely thankful to Professor Simeon Oka for his support and co-operation in preparation of the special issue, which was not a simple task.