I tutor English to my Japanese boss. This book is a treasure to have for any Japanese who wants to improve his/her email writing skills. Competent Japanese software engineers like my boss can make full use of a self-study book such as this. Frankly speaking, if you are serious about improving your email writing skills, what you need is a book with realistic and practical examples that you can use as references when you try to compose email messages effectively fast. IMHO, this book can offer a good insight into the technique of accurate and precise email writing in a variety of work-related situations.