The book is designed to help language teachers write better tests, taking the view that test construction is an exercise in problem-solving, with every teaching situation presenting a different problem that an understanding of the underlying principles of testing can help solve. Examples are given from testing of English as a Second Language (ESL). The first chapter discusses the relationship between teaching and testing, and the second presents the notion of testing as problem-solving. Various kinds of tests (proficiency, achievement, diagnostic, placement) and testing (direct/indirect, discrete-point/integrative, norm-referenced/criterion-referenced, objective/subjective, communicative) are reviewed in the third chapter. Test validity and reliability are discussed in chapters 4 and 5. The potential for "beneficial backwash," or learning from the testing experience, is explored in chapter 6. Chapters 7 and 8 outline stages in test construction (writing specifications, writing the test, pretesting, validation) and techniques for testing overall ability through multiple-choice items. Five subsequent chapters discuss testing techniques in relation to particular abilities: writing; oral ability; reading; listening; and grammar and vocabulary. A final chapter lists considerations and procedures in test administration. An article on statistical analysis of test results, questions from one standardized English test, a bibliography, and an index are appended. (MSE)