Book excerpt: Errors in Language Learning and Use is an up-to-date introduction and guide to the study of errors in language, and is also a critical survey of previous work. Error Analysis occupies a central position within Applied Linguistics, and seeks to clarify questions such as `Does correctness matter?', `Is it more important to speak fluently and write imaginatively or to communicate one's message?' Carl James provides a scholarly and well-illustrated theoretical and historical background to the field of Error Analysis. The reader is led from definitions of error and related concepts, to categorization of types of linguistic deviance, discussion of error gravities, the utility of teacher correction and towards writing learner profiles. Throughout, the text is guided by considerable practical experience in language education in a range of classroom contexts worldwide.