Barbara Gittings
Barbara Gittings was a librarian, gay rights activist, and editor of lesbian magazine The Ladder, published by the Daughters of Bilitis. She marched with Frank Kameny in Washington DC, she helped get the American Psychological Association to remove homosexuality from the DSM, and she was very active in ALA’s Taskforce on Gay Liberation (which has now morphed into the GLBT Round Table), including its Hug A Homosexual booth at the 1971 annual conference. You can read more in her history of the taskforce, Gays in Libraryland.
Photo is from the NYPL Digital Gallery.