Elementary: Mark Foley and Diane Hall
Diane Hall has been involved in English Language Teaching and Publishing for over 25 years. She taught for several years in the UK and Germany before moving into publishing and writing. She has written a number of books, notably the Longman Advanced Learners' Grammar and Distinction, a course for advanced learners (with Mark Foley). Diane has a teaching qualification in ELT and an MA in Second Language Learning and Teaching from the University of London.
Mark Foley has worked in English Language Teaching for over 23 years and has extensive experience in teaching (mostly in the UK and Spain), teacher training, examining and materials writing. He is the co-author of a number of publications, including the Longman ELT advanced titles Distinction and Advanced Learners' Grammar.
Pre-intermediate: Richard Acklam and Araminta Crace