Trixy is a 1904 novel by the best-selling but largely forgotten American author and women’s rights activist Elizabeth Stuart Phelps. The book decries the then common practice of vivisection, or scientific experiments on live animals. In Trixy, contemporary readers can trace the roots of the early animal rights movement in Phelps’s influential campaign to introduce legislation to regulate or end this practice. Phelps not only presents a narrative polemic against the cruelty of vivisection but argues that training young doctors in it makes them bad physicians. Emily E. VanDette’s introduction demonstrates that Phelps’s protest writing, which included fiction, pamphlets, essays, and speeches, was well ahead of its time. Though not well known today, Phelps’s 1868 spiritualist novel, The Gates Ajar, which offered a comforting view of the afterlife to readers traumatized by the Civil War, was the century’s second best-selling American novel, surpassed only by Uncle Tom’s Cabin. Recently scholars and readers have begun to reexamine Phelps’s significance. As contemporary authors, including Peter Singer, Jonathan Safran Foer, Donna J. Haraway, Gary L. Francione, and Carol J. Adams, have extended her vision, they have also created new audiences for her work.