Not much is known about Harriet Mill. There is no biography, and almost any information about her is filtered through the scholarship on her husband, John Stuart Mill. Mill himself was careful to guard his wife's privacy, even after her death. When the American suffragist Pauline Wright Davis asked Mill in 1870 about the possibility of composing a memoir about his wife, he responded that it would be of great benefit to humanity to portray in biography a mind like hers. "But such a psychological history is seldom possible," he argued, "and in her case the materials for it do not exist. All that could be furnished is her birth-place, parentage, and a few dates." Mill may have destroyed the materials that could have shed light on his wife's life, but more likely she led a relatively uneventful life and was most preoccupied with intellectual matters. We do know that she was born Harriet Hardy and, in 1826, married John Taylor, a merchant. When she met Mill (probably in 1830), she was already the mother of two sons; her daughter, Helen, was born in 1831, by which time Mill and Harriet had already forged a strong friendship. After a trial separation in 1833, Taylor accepted his wife's friendship with Mill, but at least one of Mill's friends seems to have broken with him over what was thought by some to be an "improper" relationship. Taylor died in 1849, and, in 1851, when both Mill and Harriet were in failing health, they married. They took up residence in Avignon, where Harriet died seven years later. There is much speculation as to the true nature of the relationship between Harriet and Mill during the years when Taylor still lived. Though in 1831 Harriet said that her relationship with both her husband and Mill was one of "Seelenfreundin," or "soul-kinship," her explanation does little to defuse conjecture. Her intellectual contribution seems much clearer, but even here, there is little empirical evidence of how much or how little she actually had to do with the composition of some of Mill's most important writings. Some scholars have postulated that she is the unacknowledged co-author of "On Liberty" (1859), "The Subjection of Women" (1869), and the "Autobiography" (1873), all of which were published after her death. Yet the only work for which she is indisputably credited is her essay "Enfranchisement of Women." Whatever her contribution, Mill, in the introduction of "On Liberty," calls her "the inspirer, and in some part the author of all that is best in my writings." Certainly she was a tireless advocate of women's and workers' rights throughout her life.