Language testing lies at the core of both language teaching and applied linguistics. This is the challenging view set out by Alan Davies in this account of the principles and place of language testing today. Testing provides a means of establishing goals and standards for courses and syllabuses. For both teacher and learner it monitors success in attaining targets. But testing too provides a methodology for experiment and investigation in applied linguistics. Not only does it lend its techniques to research throughout discipline, but it also encapsulates many fundamental issues in the field. The practice of testing raises pervasive questions for example about the sampling of language and the problems of establishing reliable and valid criteria. Central to this book is the view that teachers and researchers must always accept the need creatively to compromise between the demand for explicitness and the underlying uncertainty of language testing. Drawing on many years experience and reflection, this is a considered and thoughtful account of the principles and procedures fundamental to language testing.