Vivian Maier, of French and Austrian descent, was born in New York City in 1926. For 40 years she worked as a governess for a family on Chicago’s North Side. But in the early morning and afternoons she ventured out, snapping photographs of the people who walked the streets. Though domestic service may seem incompatible with artistic ambition, a street photographer, like a governess, lives on the sidelines, there but not there. Living in New York from 1951, then moving to in Chicago in 1956, Maier documented a turbulent time in American history, when urban life was shifting into modernity. Though her photography wasn’t discovered until 2007 (just two years before she died), her work quickly rose to eminence. A full array of Maier’s art sheds light on this mysterious woman. —E.C.