The role of writing in social interactions is becoming more and more evident in modern communities. The increasing use of personal computers and the rapid growth of the Internet have emphasized the importance of writing skill among the four skills. As a result, the ability to speak and write a second language is becoming widely recognized as an important skill for educational, business, and personal reasons. The use of performance assessment as a measure of writing language skills in English as a second or foreign language has become a common practice all over the world. This book provides an assessment model that can help teachers to observe and evaluate student writers' performances during the writing process. We hope that applying such a model for writing assessment can provide teaching practitioners with a better diagnostic tool for the evaluation of learners who are more likely to perform differently in different stages of the writing process.