It became already tradition for the journal Thermal Science to publish selected papers from SDEWES Dubrovnik Conference. This year is the 6th time that we present in the journal Thermal Science papers presented at the 8th Dubrovnik Conference on Sustainable Development of Energy, Water and Environment Systems, held from September 22 to 27, 2013, but this time in Part two of this issue we published also selected papers presented at the 16th Symposium on Thermal Science and Engineering organized by Society of Thermal Engineers of Serbia, held in Sokobanja, Serbia, from October 22 to 25, 2013. Both conferences are devoted to sustainable development, but the Symposium in Sokobanja is more oriented to the specific problems in Serbia. Selection of papers made by Guest editors of both Parts of this issue was aimed to point out main problems and tasks of the energy systems, and in strategies of scientific and technology development, necessary to be solved in the countries of the South East European region, if they want to satisfy modern requirements of the European Union, since all of them are members or candidates for entering European Union. In spite of the fact that energy, environmental, and water problems are common for in all European countries, countries in the region have an additional problem - their energy systems are relying on the only domestic energy potential - low quality coal, energy efficiency is low, use of renewable energy sources are at the beginning, and environmental, mostly waste management problems, are difficult to be solved in near future due to economical problems. Editorial Board of the journal Thermal Science believe, that papers selected will greatly contribute to the formulation of the long term polities in energy, water, and environment in the countries of the South East European region. I am deeply grateful to the Guest editors, Professors Daniel R. Schneider, Zvonimir Guzović, and Neven Duić, for their excellent selection of papers published in Part one of this issue, as well as to Profesor Mladen Stojiljković for difficult task to select only 9 papers from the Symposium in Sokobanja in Part two. I am sure that selected papers will greatly help scientists, engineers, and decision making experts in the countries of the South East European region to obtain realistic insight in the problems that are necessary to be solved in order to overcome problems in energy supply, and may be most important to start mutual co-operation and preparation of the joint scientific and R&D projects to solve difficult problems in the region.