Decisions which can be made from test results, especially in the case of progress and achievement tests, can be misleading if the decision is based on tests which lack content validity.The classroom tests need to be the direct reflection of the contents of the textbook. This can help learners to be proficient and successful in their learning as it has been intended. This requires a test which provides learners with all the major and sub-language skills and appropriate testing techniques. Such tests can provide information about students’ performance in every content area. A test which lacks content validity is unlikely to be accurate. Such a test is likely to have harmful backwash effect. Areas which are not tested are likely to become areas ignored in teaching and learning (Hughes 1989). In relation to this, many testing scholars have emphasized the need for content validity for classroom progress and achievement tests. Therefore, this book can: Inform both teachers and students the aim of testing. Provide readers (teachers) with the techniques of assessing content validity of tests.Inform teachers the areas that should be covered in tests.