The Stirling heat engine was first patented in 1816 [1]. It was a form of closed-cycle hot air engine, which, in itself, was not a new concept, even in the early nineteenth century. However, in Stirling＇s version there was a crucial innovation that made the engine unique-a regenerative heat exchanger. This was a remarkable invention, considering the state of knowledge of thermodynamics and heat transfer at the time. Moreover, Stirling, in his original patent document, foresaw the many future uses the regenerative principle could be put to in iron, steel, and glassmaking processes. The inventor of the regenerator-he called it an economizer-worked with his brother James to perfect the device, and by 1845 their experimental investigations had clearly identified the complexities of balancing the conflicting requirements for enhancing heat transfer and reducing gas dynamic drag [2]. Their contributions to the field of regenerative heat transfer have never been universally acknowledged. It is hoped that this article will help to redress this situation.