Increasingly, items have appeared on the Internet reporting the appearance of handprints on home mirrors and windows, inside and outside. The odd shapes and sizes observed have lead reporters to suggest that they have spirit or alien sources. Often they are photodocumented. We became interested in the topic when we were asked to evaluate a double-pane thermal window on which handprints had recently appeared. The window had been in place for more than 20 years. The prints all appeared on the (...) same inside surface (same pane). The two panes were, surprisingly, separated by 0.25 inch. Keywords: handprints ___ flash photography ___aliens___spirits___glass____mirrorsv. (shrink)