Heat pipes are used widely in space technology, nuclear power conversions, heat transfer systems, cellular phones, cooling of computers and in several other industrial operations. Heat pipes are based on the models of heat exchangers which are used for transportation of thermal energy over long distances with minimal temperature difference. There are various kinds of heat pipes available with modified designs and techniques like Constant Conductance Heat Pipes (CCHPs), Variable Conductance Heat Pipes (VCHPs) and Diode Heat Pipes, etc. This comprehensive book encompasses sections on all the significant aspects of heat pipes, theoretical principles behind their functioning, modifications & designs and their wide scope of applications. It is a beneficial text for students, researchers, engineers and readers in general who are keen to enhance their knowledge on heat pipes.