This book examines political participation, representation and legitimacy in the national parliaments of European Union countries.The book is organised around three major questions: What affects women's presence in parliaments? Does the number of women in aparliament have an effect? Do women in parliaments represent women? The evidence presented here shows that, to be effective, institutional reforms need a 'minimal environment' with respect to socioeconomic factors. Contrary to the critical mass theory, which claims that a few representatives cannot have much of an impact on political outcomes; in this book, empirical evidence suggests that smaller groups of women can influence different components of the legislative process. The final part of the book turns to the fundamental question of whether a parliament that is 'descriptively representative' - in which the parliamentarians share certain characteristics with the voters - will also be 'substantively descriptive', with parliamentarians mirroring voters' opinions. The author argues that an electoral system's level of proportionality influences the extent to which parliament and assemblies mirror their populations, socially and ideologically."