For the bubbleheaded young Narcissus of myth, the mirror spun a fatal fantasy, and the beautiful boy chose to die by the side of a reflecting pond rather than leave his “beloved” behind. For the aging narcissist of Shakespeare’s 62nd sonnet, the mirror delivered a much-needed whack to his vanity, the sight of a face “beated and chopp’d with tann’d antiquity” underscoring the limits of self-love. Whether made of highly polished metal or of glass with a coating of metal on the back,... --snip-- To scientists, the simultaneous simplicity and complexity of mirrors make them powerful tools for exploring questions...