These three questions are the Guineas from the title, and these essays are responses to them. Woolf's three questions are: Can war be prevented in the future? Why has woman's education been so underfunded, historically? And, Why can't women work the same jobs as men?
The first question begins these essays. The question was prompted to her by a letter from an educated man, she tells us. Simply put, he asks whether war could be prevented, and if so, how? Woolf responds that the culture has become so dominated by masculinity and competition that at the geopolitical level, the nations in the West are typically too aggressive to avoid war. She says another issue stands between peace in the world's politics: peace between men and the women they have historically oppressed.
That is when she diverges to the next question: What was the original assumption behind the poor funding of education for women? Why was the standard not that all people, male and female, are treated equally by the law and the market? She says that by experimenting with new types of social order, perhaps we could actually adjust for those dubious assumptions that made history's treatment of women so poor.
She challenges the idea that men and women are differently enabled by nature, because in her day, many people felt like women were actually intellectually incompetent to do "male" jobs. She says that women bring equal and different perspectives that, if they had been in balance, would flourish such that the politics might actually reflect the whole opinion of the populace, instead of allowing powerful patriarchal traditions to continue growing.
