This book looks at how the evidence of change and stability in modern political parties and party systems is interpreted. The emphasis is on western European political parties. The primary focus of the book is on processes of political adaptation and control, but it also concerns how parties and party systems generate their own momentum and ‘freeze’ themselves into place. Amidst the widespread contemporary discussion of the challenge to modern democracy and the crisis for traditional forms of political representation, it offers an emphasis on how party systems survive, and on how change, when it does occur, may be analysed and understood. The book has four parts, and the constituent chapters are from various essays reflecting work that has been carried out since the late 1980s. Part I contains an introductory chapter on the freezing of party systems. Part II has three chapters that deal with questions of persistence and change, and with the vulnerability and endurance of traditional parties. Part III has two chapters in which attention shifts to the question of party organization, and to the ways in which the established parties are increasingly coming to invade the state, finding there a new source of privilege and a new means of ensuring their own survival. Part IV has three chapters that focus on structures of competition in western party systems, as well as on the problems associated with the consolidation of the new party systems in post-communist Europe.