The implicit/ explicit distinction is central to our understanding of the nature of L2 acquisition. This book begins with an account of how this distinction applies to L2 learning, knowledge and instruction. It then reports a series of studies describing the development of a battery of tests providing relatively discrete measurements of L2 explicit/ implicit knowledge. These tests were then utilized to examine a number of key issues in SLA - the learning difficulty of different grammatical structures, the role of L2 implicit/ explicit knowledge in language proficiency, the relationship between learning experiences and learners’ language knowledge profiles, the metalinguistic knowledge of teacher trainees and the effects of different types of form-focused instruction on L2 acquisition. The book concludes with a consideration of how the tests can be further developed and applied in the study of L2 acquisition.

Rod Ellis is Professor of Applied Language Studies in the University of Auckland and a visiting Professor at Shanghai International Studies University. His publications includes articles and books on second language acquisition, language teaching and teacher education. His most recent is The Study of Second Language Acquisition 2nd Edition (Oxford University Press, 2008). He is also editor of the journal Language Teaching Research.

Shawn Loewen is an assistant professor in the Second Language Studies program at Michigan State University. He specializes in second language acquisition and L2 classroom interaction. His recent research has investigated the occurrence and effectiveness of incidental focus on form in a variety of L2 contexts.

Catherine Elder is Associate Professor in the School of Languages and Linguistics and Director of the Language Testing Research Centre at the University of Melbourne. She is coeditor (with Glenn Fulcher) of the journal Language Testing j. She is author with Alan Davies et. al. of the Dictionary of Language Testing and co-editor of Experimenting with Uncertainty (CUP: 2001) Handbook of Applied Linguistics (Blackwell, 2004).

Hayo Reinders (www.hayo.nl) is Editor of Innovation in Language Learning and Teaching. He was previously Director of the English Language Self-Access Centre and Visiting Professor at Meiji University in Tokyo. His research interests are in the areas of computer-assisted language learning and learner autonomy.

Rosemary Erlam is lecturer in the Department of Applied Language Studies and Linguistics at the University of Auckland. She comes to Applied Linguistics from backgrounds in Speech-Language Therapy and French teaching. Her research interests include teacher education, form-focused instruction and issues pertinent to the New Zealand educational context.

Jenefer Philp is a lecturer at the University of Auckland. Her experimental and classroom based research centers on the role of interaction in second language development by adults and children She has recently co-edited a book titled Second language acquisition and the younger learner: Child’s play?, published by John Benjamins.