This issue of the journal Thermal Science is in many aspects specific. For the first time we published papers covering new scientific topic - processes in nanofluids, and in the space of nano dimensions, following by a very informative review paper devoted to thermal problems in electronics. We expect in the future more papers in those modern topics. Besides, we were pushed to devote almost the half of the issue to the processes in internal combustion engines (ICE). In spite of the fact that the whole preceding issue (No. 1, 2008) was devoted to those problems, number of papers submitted for this issue was too great to be ignored, so we decided to publish those papers in this issue, making in this way continuity of the consideration of processes in ICE and use of biofuels.