Book excerpt: It is a well-known fact that the area of the present perfect has always been a hotly contested ground, but recent corpus analyses have shown that grammatical variation in this realm in English is far more pervasive than previously assumed. This volume is the first ever book-length treatment dedicated to corpus-based work on the present perfect. It offers fresh theoretical insights resting on a solid empirical footing and investigates central aspects of language contact and change, grammaticalization, typology, and dialect formation. It sheds light on this morphosyntactic area from different angles, as it comprises both diachronic and synchronic viewpoints. Contributions explore variation in the expression of perfect meaning and the multifunctionality of perfect forms in a number of native and non-native varieties, thus going beyond the traditional British/American English paradigm, while a second focus lies on cross-variety comparisons. Bringing together the knowledge of leading experts in the field, this book represents the state of the art in data-driven research on the present perfect and will be of interest for those working in the fields of language variation and change, corpus linguistics, sociolinguistics, and typology.