Joan was one of the few people to be a part of both Ayn Rand's Objectivist movement in the 1960s and the women's liberation movement in the 1970s. Her Objectivism was never dogmatic, and neither was her feminism. Unlike many feminists, she embraced a consistently individualist perspective. She was passionate in her belief that the true independence and autonomy for women meant self-reliance, not replacing dependency on men with dependency on the state, and in her opposition to paternalism of all kinds.
I knew Joan fairly well in the early to mid-1990s, when we were both active in "dissident feminist" causes, including alternative approaches to such issues as sexual harassment (Joan authored an excellent book on the topic, What to Do When You Don't Want to Call the Cops: A Non-Adversarial Approach to Sexual Harassment), pornography and speech codes (Joan was active in the anti-censorship group, Feminists for Free Expression). Unfortunately, we had drifted apart since, and in recent years I only saw her a few times at public events, looking very frail as she struggled with cancer.
Past issues of the ALF (Association of Libertarian Feminists) Newsletter, edited by Joan and featuring many of her essays, interviews, and book review, can be found here. (Hat tip: Jesse Walker at Hit & Run.)
A more detailed biography of Joan can be found here (thanks to Walter Olson for the pointer).