Research and Application on Official Documents in China Mainland is the fourth book of the series Mother-Tongue Education in Hong Kong . The book applies the modern communication theory to practical writing in China Mainland, including in government, business and administrative institutions and in other social organisations. The book pays special attention to elements of communicative writing, such as cultural backgrounds, social surroundings, authors and readers, contracts, communication media, external interferences, languages, input and output, chapters, auditors and readers’ feedbacks. All these are important communication elements of documents and could expand a new area for teaching practical writing. The study serves as a bridge between Mainland China and Hong Kong. Furthermore, the book can help people of all walks of life to cope with the difficulties they encounter in reading and writing practical documents when they co-operate with colleagues in the Mainland.