Isothermal compression/expansion is regarded as the most promising process in many applications and many researchers and inventors have tried different methods to achieve this goal. The current article first studies the gradual roadmap from adiabatic towards isothermal process from thermodynamics and heat transfer point of view. Different strategies are investigated to achieve this goal by evaluating different possibilities; the bottleneck of the problem is then identified in reciprocating pistons: most of the compression work (and hence heat generation) occurs at the end of the compression stroke, however the heat transfer surface is at its minimum by the time that a high overall heat transfer rate is most needed. Then increment of heat exchange surface (specially at this important time interval) is being focused on as the most promising solution. Based on such a concept, a novel kind of reciprocating air compressor is being developed, in which quasi-isothermal compression is achieved by increasing heat transfer through co-axial fins. Finally a global map is illustrated to show the starting point, proposed solution standing point and the ideal situation and its requirement.