The use frequency of the term `knowledge society' to characterize present Western societies is disproportionate to the clarity of its measurement and the availability of longitudinal and cross-national evidence. The author develops a conceptualization of the knowledge society that enables the study of its development in cross-national and longitudinal perspective. This conceptualization is then applied to an analysis of 19 OECD countries between 1970 and 2002. Three main sets of findings are proposed. (1) In all 19 countries a clear trend towards the knowledge society is observable. (2) From an employment perspective, societies were and still are mainly knowledge-mediation societies but are increasingly becoming knowledge-management societies; from a value-added perspective they are better described as knowledge-infrastructure societies. (3) However, developing knowledge societies di fer enormously in terms of their sectoral structures – within and outside the knowledge sector.

There are several explanations for the inequality upswing in the literature: rising globalization, the institutional re-structuring of the nation-states, as well as changes in the relation between the demand for and the supply of skills. Concerning demand changes, Kuznets and Lewis identified two inequality affecting mechanisms with regard to the agricultureto-industry transition: sector bias -that is, inequality within sectors -and sector dualismthat is, inequality between sectors. In this article it is analyzed whether there are analogue effects on inequality from the sectoral change to the knowledge society. Following the strategy of a most-similar design and a variable oriented approach the hypotheses are tested cross-nationally and longitudinally in 19 OECD countries between 1970 and 1999. To verify sectoral effects, error component models are computed regressing the Ginicoefficient on a globalization measure, the union density, the educational attainment as well as the employment and income differential in the knowledge sector. The results show that some amount of the inequality upswing in the last few decades can be explained by the sectoral change to the knowledge society.The systematic analysis of inequality variation between developed 1 countries and within countries over time is rather a new field of research (e.g. see the meta-analysis of Atkinson and Brandolini, 2004). A good proportion of theories aiming at explaining the long-term development of inequality is based on data from societies with very different levels of economic development at a rather International Journal of Comparative Sociology