A brief historical review on cryogenic engineering starting from ice and ice maker (one the earliest cryogen-free refrigerator in the cryogenics engineering history) is presented.

A background review of thermodynamics and its connections to the cryogenic engineering is discussed. Steam engine was one of the most important bridges for this connection and it stimulated people to pursue fundamental understanding on energy, work, heat, heat flow, and the relations between them.

Cryogenic engineering completed its transition from the “primitive” stage in the eighteenth century and earlier to a more mature phase in the nineteenth century, where liquefaction of gases had become the main focuses. Two most important breakthroughs were the liquefaction of “permanent gas” of Hydrogen and that of “Noble gas” of helium. A brief review of the invention of Dewar and the liquefaction of hydrogen is presented at the end of this chapter. This breakthrough laid an inevitable foundation of liquefaction of helium discussed in the following chapter.