Douglas Biber's new book extends and refines the research and methodology reported in his ground-breaking Variation Across Speech and Writing (1988), and adds for the first time a diachronic dimension. In it he gives a linguistic analysis of register in four widely differing languages: English, Nukulaelae Tuvaluan, Korean, and Somali. Striking similarities as well as differences emerge, allowing Biber to predict for the first time cross-linguistic universals of register variation.