China Labour Statistical Yearbook 2001 is an annual statistics publication, which is comprehensively reported the labour economic situations for 2000 and some main indicators series for historically years at nation and provinces, autonomous regions and municipalities levels and parts of cities, Hong Kong Special Administrative Region and Macao Special Administrative Region in People's Republic of China. The book is organized into 13 parts, which are: (1) Comprehensiveness; (2) Employment and Unemployment; (3) Employment and Earnings in Urban Units; (4) Employment and Earnings in State-owned Units; (5) Employment and Earnings in Urban Collective-owned Units; (6) Employment and Earnings in Other Ownership Units; (7) Employment in Private Enterprises and Individuals Both in Urban and Rural Areas, Employment in Township and Village Enterprises; (8) Reform. of Labour Social Security System; (9) Social Insurance and Welfare Funds; (10) Vocational Schools and Hours of Work; (11) Trade Union Works; (12) Indicators of Hong Kong. (13) Indicators of Macao. In addition, Indicators of Other Countries and Explanatory Notes for Major Indicators are provided in the end of the book. Besides National Bureau Statistical and Ministry of Labour and Social Security, State Administration Bureau for Industry and Commerce and All-China Federation of Trade Unions also participate in the compiling work of this book. Data resources of this book mainly come from state and departments reporting system, administration records and sampling surveys. Since the information of labour resources and employment for the whole country are calculated according to relevant data, they are not equal to the add-results of all sub-items. Which book's preface is this?