Tristram Potter Coffin’s The British Traditional Ballad in North America, published in 1950, became recognized as the standard reference to the published material on the Child ballad in North America. Centering on the theme of story variation, the book examines ballad variation in general, treats the development of the traditional ballad into an art form, and provides a bibliographical guide to story variation as well as a general bibliography of titles referred to in the guide. Roger deV. Renwick’s supplement to The British Traditional Ballad in North America provides a thorough review of all sources of North American ballad materials published from 1963, the date of the last revision of the original volume, to 1977. The references, which include published text fragments and published title lists of items in archival collections, are arranged according to each ballad’s story variations. Textual and thematic comparisons among ballads in the British and American tradition are made throughout. In his introductory essay Renwick synthesizes the various theoretical approaches to the phenomenon of variation that have appeared in scholarly publications since 1963 and provides examples from texts referred to in the bibliographical guide itself. The supplement, like its parent work, is an invaluable reference tool for the study of variation in ballad form, content, and style. Together with the reprinted text of the 1963 edition, the supplement provides an exhaustive bibliography to the literature on the British traditional ballad in North America.