The area of Beijing Mandarin in this book covers Beijing city and its subordinate districts and counties, Tianjin City and its subordinate districts and counties, Chengde City, Baoding City, Tangshan City, Qinghuangdao City and Langfang City in Hebei Province and their subordinate districts and counties, Chifeng City, Hailar City, Tongliao City and other areas in Inner Mongolia Autonomous Region and the Northeastern areas north of the Liaodong Peninsula. The book gives an overall and profound description and analysis of many aspects of Beijing Mandarin, such as its distribution, formation and development, its internal variations and sub-categories, and the initials, finals and tones in it, putting forward many innovative points of view which can serve as reference for such programs as the sound discrimination of Putonghua and the revisions and improvements on the policy of popularizing Putonghua.