From Afghanistan to Zimbabwe the world has witnessed a rising tide of contentious elections ending in heated partisan debates, court challenges, street protests, and legitimacy challenges. Despite growing concern, until recently little research has studied this phenomenon. To understand contentious elections, this book brings together scholars using a range of fresh evidence. The editors, from the Electoral Integrity Project, develop the theoretical framework and then draw together the main findings in the introduction and conclusions. The book provides insights invaluable for studies in democracy and democratization, comparative politics, international relations, and political behavior.