Book excerpt: This book investigates –s marking in English verbs, specifically its manifestations in main verbs, in the past tense of BE, and in existential constructions. It embraces the many ways in which –s marking varies across the English speaking world, and considers both how it arose in these places historically and the ways in which it has since developed. The authors propose a story which holistically accounts for these different manifestations of –s, drawing upon evidence from a wide range of subdisciplines in linguistics, including sociolinguistics, generative syntax, historical linguistics, dialectology, and discourse-pragmatics. This book will be of particular interest to students and scholars in these and related fields.