Applications of microscale and nanoscale thermal and fluid transport phenomena involved in traditional industries and highly specialised fields such as bioengineering, micro-fabricated fluidic systems, microelectronics, aerospace technology, micro heat pipes, and chips cooling etc., have become especially important since the late 20th century. However, microscale and nanoscale thermal and fluid transport phenomena are quite different from those of conventional scale or macroscale. Many researchers have been conducting research on the thermal and fluid transport phenomena at the microscale and nanoscale levels to understand the very complex phenomena involved. New methods have been applied to measure the basic physical parameters at microscale and are continuously under development. New prediction methods have also been developed to cover both macroscale and microscale channels and are being continuously investigated. New theories and mechanisms are also urgently needed for the fluid flow and heat transfer phenomena at microscale and nanoscale. There are many issues to be clarified from both theoretical and applied aspects in the microscale and nanoscale thermal and fluid transport phenomena. Furthermore, interdisciplinary research areas are also rapidly under development. For example, as a new research frontier of nanotechnology, the research of nanofluid two-phase flow and thermal physics is rapidly growing. However, it has also posed new challenges as there are quite contradictory results in the available research.