Levitt did the bulk of her work from the late 1930's up to the 1990's. She shot mostly street life in New York City.
Starting out with photography she worked for a commercial photographer, but was inspired to do her own work when she bought her leica camera and began to shoot children and their chalk drawings that had become a part of the street culture in New York City.
The photos were published under the title "In the Street: Chalk Drawings and Messages, New York City 1938-1948"
Here is an example of that work. You can see more here
From what I have read about Levitt was that she just shot people going about their everyday life. When she started working in color a large amount of her work was stolen from her apartment in 1970.
After the robbery Levitt started over again and worked through the 70's on new pieces. Forty of the images from this body of work were shown in a slide show at the New York Museum of Modern Art in 1974. This was a huge deal since it would have been one of the fist times photographs would have been shown that way in a museum, and it was one of the first exhibitions of color photography anywhere.
I really love photography that seems to have a sense of reality to it, photographs that capture more than just someone with a fake smile or a pretty face; photographs that capture something more that what is just in front of the lens, photographs that make some sort of commentary about the time, the culture or the place.
Here is an example of her color photography work. You can see more here.
Some information was taken from : lensculture.com