Long gone are the times when class-based political parties with extensive membership dominated politics. Instead, party politics has become issue-based. Surprisingly few studies have focused on how the issue content of West European party politics has developed over the past decades. Empirically, this books studies party politics in Belgium, Denmark, France, Germany, the Netherlands, Sweden, and the UK from 1980 and onwards. The book highlights the more complex party system agenda with the decline, but not disappearance, of macroeconomic issues as well as the rise in ‘new politics’ issues together with education and health care. Moreover, various ‘new politics’ issues such as immigration, the environment, and European integration have seen very different trajectories. To explain the development of the individual issues, the book develops a new theoretical model labelled the ‘issue incentive model’ of party system attention. The aim of the model is to explain how much attention issues get throughout the party system, which is labelled ‘the party system agenda’. To explain the development of the party system agenda, one needs to focus on the incentives that individual policy issues offer to large, mainstream parties, i.e. the typical Social Democratic, Christian Democratic, or Conservative/Liberal parties that have dominated West European governments for decades. The core idea of the model is that the incentives that individual policy issues offer to these vote- and office-seeking parties depend on three factors, namely issue characteristics, issue ownership, and coalition considerations. The issue incentive model builds on and develops a top-down perspective on which the issue content of party politics is determined by the strategic considerations of political parties and their competition with each other.