“All [Picasso’s] portraits of me are lies. They’re all Picassos. Not one is Dora Maar,” said the woman in question. Maar (1907–1997) was Picasso’s lover and muse, but she was also a prolific photographer and painter in her own right. Her black and white shots focused on nudes, fashion advertising, and portraiture, the images elegantly, often hauntingly, surreal. In this unprecedented auction, 750 never-before-seen photographs by Maar are up for grabs. What secrets do they harbor? —E.C.