The famous author known for her radical ideas on women's rights in the 17th century was Mary Astell. Considered one of the first English feminists, Astell’s work "A Serious Proposal to the Ladies" argued for the importance of education for women and critiqued the prevailing societal norms that restricted their roles. She believed women were capable of intellectual pursuits and deserved educational opportunities on par with men. Astell's writings not only challenged gender inequalities of her time but also laid groundwork for future discussions on women's rights, emphasizing the need for women’s autonomy and self-improvement.