New in softcover. Hardcover was published in 2021. This Handbook includes a contextual section on the history of referendums, the theoretical questions underpinning their use, and on constitutional and legal questions about the use of referendums. The empirical sections are divided into those referendums that focus on domestic issues, such as constitutional matters or questions of social policy, and those related to the European Union, including membership referendums and treaty ratification.