Temporal artery (TA) thermometry was developed in answer to requests by pediatricians for a replacement for: 1) ear thermometry due to inaccuracy; and 2) rectal thermometry due to parents’ (and most clinicians’) growing dislike of the method. The underlying technology development spans some 20 years, borrowing heavily from methods invented for industrial processes and medical research. Although the forehead has been used since antiquity to detect fever, its accuracy had always been questionable until physiological artifacts were understood and overcome, and mathematical modeling of arterial heat balance at the skin has made it possible to produce accurate core temperatures entirely non-invasively with just a scan of the forehead. Clinical studies have been conclusive as to TA superiority to ear thermometry, and well on the way to being conclusive as to TA at least as accurate as rectal. The physics are relatively straightforward, but the physiological requirements are not. Underlying physiological artifacts cause errors of more than 2 deg C in non-invasive thermometry and must be reduced by an order of magnitude to provide medically useful temperatures. Patented TA technology incorporates methods of dealing with physiological artifacts to overcome these errors. Mass screening for SARS containment with this method is examined.