The Societies of Europe is an 8-title series of historical data handbooks and accompanying CD-ROM sets, on the development of Europe from the nineteenth to the twentieth century. The series is a product of the Mannheim Centre for Social research, a body dedicated to comparative research on Europe and one of the leading social research institutes in the world. It is a collection of datasets giving a clear and systematic study of long term developments in European society. The data is presented statistically and is clearly comparative. The Societies of Europe is the most comprehensive data series available on Western European social issues. Each book is accompanied by a CD-ROM containing data sets not included in the text enabling users to manipulate the data as wanted. Information is available in different programmes (Excel, SPSS and SAS) and in data structures for analysis, viewing and building time series. This comparative data handbook offers an empirical base to a long-term and comparative understanding of changes and variations in European union movements. It provides information on the context and history of union development, the changes in the structure of post-war unionism until today, the long-term trends in union membership and union density, and the shifts in the cross-sectional composition of union membership. This book and CD-ROM are the result of many years of research by the authors in collaboration with an international research team, and provides an original source for comparative and national studies or individual enquiries. The country and comparative tables offer cross-checked and often newly-calculated statistics on national union organizations and their membership series. The CD-ROM includes selected tables from the handbook and provides additional databases with organizational data and membership series of major national and European union organizations.