The planning of this volume started out in response to the question: What are the implications of second language acquisition research for language teaching? The aim of the book is therefore to give this question an in-depth consideration from various points of view. The discussion centres around issues such as whether and how teaching, teaching materials and testing can be planned and executed in ways that are more favourable for the individual learners, if known facts about second language acquisition are taken into account. As the title of the book suggests, it is divided into two parts. Part I deals with those factors which concern syllabus design, teaching materials, and teaching itself. Part II is concerned with assessment testing.