The range of temperatures considered in cryogenics appears to be quite small, a few hundred kelvin, when compared with the millions of degrees encountered, for example, in the plasma region. However, much fundamental work in physics is done at temperatures well below room temperature. In fact, a logarithmic scale for the temperature values is a more realistic way to portray the temperature scale than a linear one. Temperatures far below the minimum existing in nature (background cosmic radiation, 2.75 K) are commonly attained in laboratories, decades farer in value from room temperature than plasma temperatures are. Many updates and substantial improvements took place in cryogenic thermometry in the past 10 years. Their illustration is the aim of this paper.
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