Made internationally famous by the publication of her post-Civil War spiritualist work, The Gates Ajar (1868) -- a novel outsold in the nineteenth century only by Uncle Tom’s Cabin -- Elizabeth Stuart Phelps became in the last decades of the century a leading figure in American literature. Phelps used her prominence to advocate for spiritual uplift and social change -- especially “Heaven, homeopathy, and women’s rights.” As a self-described “professional invalid” who suffered from a chronic “nervous disease,” Phelps interested herself in the medical education and practice of women, befriending and consulting several women physicians, and in her writing “advanced compelling critiques of the medical profession and its treatment of women.” In, for instance, two pieces written in 1874, Phelps disputes the claims of Harvard Medical School Professor E.H. Clarke that higher education causes physiological harm to women. A decade later, Phelps initiated a correspondence with the eminent neurologist Silas Weir Mitchell in which they discussed their mutual interest in medical fiction, and Phelps challenged Mitchell by advocating for women physicians and a homeopathic treatment of neurological illnesses. Phelps’s feminist and homeopathic response to Mitchell and mainstream neurology is the subject of her 1882 novel, Doctor Zay, in which a female homeopath cures and simultaneously reforms a male neurasthenic.