Jack C. Richards 
Error Analysis [PDF ebook] 
Perspectives on Second Language Acquisition

The eleven essays in this book cover a wide range of topics from the role of 'interlanguage’ and the influence of external factors on the process of language learning, to the development of syntax and the methodology of error analysis. Collectively they provide a valuable perspective on the learning process, which both enriches our theoretical understanding of the processes underlying second language acquisition and suggests ways in which teaching practice may best exploit a learner’s skills.