The economic environment became harsh. Market competition globalised and intensified, putting new pressures on the established national regimes of industrial relations. The industrial core of the trade union membership faced massive job losses and rising job insecurity. The target audience of the trade unions in Europe, the work force, has after all also changed considerably in recent decades. This transformation can be described in socio-demographic terms as increasing feminisation of the labour force and as a limited influx of migrant workers. Class was already a central concept in the thinking of the trade unions: working-class position, working-class consciousness, working-class solidarity, working-class action, working-class politics. However, the power of attraction of this concept reached beyond the trade unions ideology. Like the trade unions, academic class analysis has come up against a number of limits in recent decades. The chapter also presents an overview of key concepts discussed in this book.