J. K. (Jack) CHAMBERS is Professor of Linguistics at the University of Toronto. He is the author of Sociolinguistic Theory: Linguistic Variation and Its Social Significance (second edition, 2003), co-editor, with Peter Trudgill and Natalie Schilling-Estes, of The Handbook of Language Variation and Change (2002) and co- author, with Peter Trudgill, of Dialectology (second edition, 1998), as well as other books and scores of articles. He works extensively as a forensic consultant and maintains a parallel vocation in jazz criticism, including the prize-winning biography Milestones: The Music and Times of Miles Davis (1998).