A natural focus when designing an electronics product is, well the electronics. The electronics itself however, needs to work within some kind of enclosure, be it a standardized rack system, or a custom-built enclosure like the housing of a SmartPhone or tablet computer, or part of another product like an automotive dashboard or aircraft flight deck. In all cases, the electronics have to be designed with the enclosure in mind, as the enclosure can act as either a barrier or a conduit for carrying the heat away to the ambient, or possibly both. Cooling is a system issue, which is why we advocate a top-down approach, starting at the enclosure level.