Social law and policy have been moving increasingly into the mainstream of the European Union. In recent years there have been important changes to the Treaty framework for enacting social policy, bringing the role of the social partners to the fore. New Treaty provisions for adopting discrimination legislation have highlighted the potential role of the EU in combatting aspects of social exclusion, and in challenging disturbing phenomena such as racism and xenophobia. Social policy is increasingly linked to the emerging notion of Union citizenship. The arrival of the single currency in 1999 is now matched by a more pro-active EU-level policy on employment and the labour market. The analyses in this collection address these and other questions against the backdrop of the longstanding controversies over the nature and scope of EU social policy, including the UK's opt-out from certain provisions between 1993 and 1997, and the ongoing debate about whether EU social policy has, or should have, a social or an economic rationale.