European infrared, optronic and radio-frequency electronics are expanding faster than the layer beneath them is being examined. Attention concentrates on detectors, semiconductors and complete modules, because those are where performance is specified and where programme risk is usually registered. Yet every sensitive die in a thermal imager or a transmit-receive module has to be connected to the outside world, protected from moisture and contaminants, and in the more demanding applications held under a controlled internal atmosphere or a vacuum, while the assembly continues to meet its thermal, electrical and mechanical requirements. Ceramic-to-metal packages, hermetic feedthroughs and brazed interfaces perform those functions. They are unglamorous, they are cheap relative to the die they protect, and their apparent simplicity invites the wrong procurement question.