Diane Arbus was one of the most influential and imaginative photographers of the 20th century. Her work, which was at its peak in the 1960s, mainly consisted of commercial portraits, for magazines such as Esquire and Harper's Bazaar. Still they had her unique style and feel to them. They began to assume a distinctive look. Though taken of mainly traditional subjects -- actors, writers, activists -- they were strange and obscurely troubling. She would spend hours with her subjects, following them to their homes or offices, talking and listening to them, trying to soften them up to the point where they began to drop their public façade. Her images focus on the bizarre side of human beings. See her portfolio here.