This book explores the impact of electoral rules on political party development in Central and East Europe. It finds that ‘high district magnitude’ proportional electoral systems encourage centralised organisational development and campaigning – where communication with voters is conducted primarily via mass, social and digital media – while small electoral districts stimulate grassroots campaigning. As a result, low magnitude electoral systems are more likely to create an active role for party members, stimulating membership recruitment. The book further examines how parties organise and campaign on the ground. The analysis of in-depth surveys and interviews with party elites in Estonia, Lithuania and Slovakia sheds light on areas of party life that are rarely examined, including party fundraising. Overall, the effects of electoral systems on party organisation and campaigning reflect patterns previously observed in Western Europe, demonstrating that a degree of convergence has occurred.