Lillian Susan Harman-O'Brien[1] (née Harman; December 23, 1869 – 1929) was an American sex radical feminist and editor.

Her father Moses Harman edited Lucifer, the Light-Bearer, a regional, weekly paper that introduced her to issues of women's sexual freedom.

After her mother's death when she was seven years old, her father moved the family to Valley Falls, Kansas, where he joined the National Liberal League.

Harman was convicted for breaking the Kansas Marriage Act of 1867 and served prison time when she refused to pay court costs.

The case's publicity made her a national icon for women's sexual freedom and spurred other feminists to debate age of consent and marital rape.

[2][3] As the case's influence spread, Lucifer rode a wave of new subscribers to become America's pulpit for sex radicalism.