This book examines developments in the use of the present perfect and the preterite in Late Modern and contemporary English, with a focus on American and British English. Drawing on neo-Gricean pragmatics, it proposes a novel and principled analysis of the verb forms' context-independent meanings and context-dependent inferences. State-of-the-art corpus linguistic methods are used to track their functional changes over two and a half centuries. The book presents new evidence of grammatical change and offers a compelling, contact-based account of regional variation. It brings together the insights of various fields, including formal semantics, historical linguistics, linguistic typology, and variationist sociolinguistics.