What are the terms of seeing and believing? Or more specifically, how do pictures shape and direct religious faith? Kristin Schwain takes up these questions in Signs of Grace: Religion and American Art in the Gilded Age, focusing on four different American artists—Thomas Eakins, Henry Ossawa Tanner, F. (Fred) Holland Day, and Abbott Handerson Thayer—and explaining how they “drew on religious beliefs and practices to explore new relationships between viewers and objects, and how beholders...