According to Encyclopedia Britannica:
Street photography, is a genre of photography that records everyday life in a public place. The very publicness of the setting enables the photographer to take candid pictures of strangers, often without their knowledge. Street photographers do not necessarily have a social purpose in mind, but they prefer to isolate and capture moments which might otherwise go unnoticed.
He is one of my favorite street photographers (1908-2004). A French photographer whose photographs helped establish photojournalism as an art form. That photography can capture the meaning beneath outward appearance in instants of extraordinary clarity was one of his theories.
Magnum Photographers presents some of his work on their website.
To me, photography is an art of obsevation. It's about finding something interesting in an ordinary place. I've found that it has little to do with the things you see, and everything to do with how you see them.