New trends in researching language have emphasized the significant role of personality factors and individual differences on the quality of learning languages. It is nowadays believed that the personality type each person possess may hinder or facilitate the process of learning or teaching language. Therefore teachers and instructors are expected to pay more detailed attention to the individuality of learners in their classes. The present research project investigated the relationship between personality type and the writing performance of English learners. A step by step process of research in this book is a truly valuable source for those who want to learn how to conduct researches in this area of research. A well-established framework about the similar researches done in the past as well as a solid theoretical framework has made this book a valuable guide for enthusiastic researchers in this field of research.