At first glance, engineering thermodynamics may appear to be a dead discipline, but closer examination reveals a remarkably lively field of study. Its axioms have recently been reformulated in terms of heat transfer instead of mechanics. New graphic constructions are being used to summarize properties. Exergy analysis and refigeration techniques are active pursuits for many engineers. The paper discusses the common structure of opposed axiomatic formulations. Aspects of thermodynamic design and irreversible power plants are also discussed.