Our technology is completely new. Conventional, passive pyrometers are like ancient analog computers, hardwired to perform one calculation over and over again no matter the situation. Our SpectroPyrometers are modern digital computers, expert systems that actively analyze the data they collect and make decisions on how to determine the true temperature. Our approach is necessary, because real thermal targets are not well-behaved. Unlike the proverbial leopard, they can and do change their ‘spots’ if we understand ‘optical behavior’ (or emissivity) for ‘spots’. The articles under this attempt to explain both the need for the new technology and How It Works.