Warm people (as opposed to cryogenic experts) whose project includes cryogenics will find it useful to have some familiarity with a few of the basic principles and common standard practices in cryogenics. These include methods of refrigeration, heat transport modes, piping stability, and safety and compliance issues. Common cryogenic system components, such as lambda plugs, Kautzky valves, bayonets, and wet engines are described, and some mysteries of cryogenics at Fermilab are explained.