Vivian Maier, who worked mostly in domestic service, mostly in Chicago, was a serious photographer who shot some 100,000 images over upward of 40 years. Although those who knew her — primarily the children in her care; she had no real intimates — were aware that she took pictures, she never published or exhibited them, and rarely showed them to others. Her work came to general attention only when, in 2007, two years before her death, five storage lockers on which she had failed to keep up payments were emptied and their contents auctioned off. By the time the buyers realized what they had on their hands, she had died. John Maloof, who bought most of it, put up a selection of scans on a website, which immediately went viral; Maier posthumously became a media sensation. Maloof’s VIVIAN MAIER: A Photographer Found (Harper Design, $80), with text by Marvin Heiferman, is already the fifth book of her photographs to have been published…….