This Companion examines a number of issues related to the terms realism and naturalism. The introduction seeks both to discuss the problems in the use of these two terms in relation to late nineteenth-century fiction and to describe the history of previous efforts to make the terms expressive of American writing of this period. The Companion includes ten essays which fall into four categories: essays on the historical context of realism and naturalism by Louis Budd and Richard Lehan; essays on critical approaches to the movements since the early 1970s by Michael Anesko, essays on the efforts to expand the canon of realism and naturalism by Elizabeth Ammons; and a full-scale discussion of ten major texts, from W. D. Howell’s The Rise of Silas Lapham to Jack London’s The Call of the Wild, by John W. Crowley, Tom Quirk, J. C. Levenson, Blanche Gelfant, Barbara Hochman, and Jacqueline Tavernier-Courbin.