Over the 1980s unions have lost about 5 million members in OECD countries. The proportion of unionized workers is increasing in the services, public sector and among women. Today, almost two out of five union members are employed in the public sector. Wide differences remain in the levels of unionization in diverse countries, while in the United States, France and Spain union members account now for little more than 10% of the labour force, in the Nordic countries (Sweden, Finland and Denmark) the corre''sponding figure is between 75 and 85%. In general, rates have been higher in Europe than in North America. Economic analysis is paying increasing attention to these developments and to their policy implications (Edwards, Caronna and Todling, OCDE 1991). Recent progress in economic theory has enabled some light to be cast on the determinants of unionism, on the other hand, efforts aimed at coming to grips with the economic reality of unions have significantly contributed to theoretical advancement by extending and modifying conventional microeconomic wisdom. The reader of this volume will judge whether the insight gained is sufficient, or - as a recent survey concluded ~ the problem has proved to be virtually intractable (Johnson, p. 24). These can be grouped under three headings, corresponding to the three parts of the volume, which will be illustrated in the Introduction.
