Jan Svartvik is Emeritus Professor at the University of Lund, Sweden. He is co-author of A Communicative Grammar of English (with Geoffrey Leech) and A Comprehensive Grammar of the English Language (with Randolph Quirk, Sidney Greenbaum and Geoffrey Leech). He has published on other varied aspects of English linguistics, such as corpus linguistics, forensic linguistics, contrastive grammar and nautical terminology. He is a Member of the Royal Swedish Academy of Sciences, The Royal Academy of Letters, History and Antiquities and Academia Europaea. Geoffrey Leech (1935-2014) was Research Professor of Linguistics at Lancaster University, UK. Author, co-author, or co-editor of some 25 books and 100 papers or articles on varied aspects of linguistics and the English language, he was a Fellow of the British Academy and a Member of Academia Europaea. He was the author of widely used introductions to Semantics and Pragmatics, co-author with Mike Short of A Linguistic Guide to English Poetry, and co-author with Margaret Deuchar and Robert Hoogenraad of English Grammar for Today: A New Introduction.  David Crystal is Honorary Professor of Linguistics at the University of Bangor. He is the author or editor of over a hundred books on aspects of linguistics and the English language, such as The Cambridge Encyclopedia of Language, The Cambridge Encyclopedia of the English Language, The Stories of English, Language and the Internet, and Evolving English. He is a Fellow of the British Academy, and in 1995 was awarded an OBE for services to the English Language.