Chapter I. Political Parties Transition into the Digital Era.- Chapter 2. The Five-Pillar Model of Parties' Migration into the Digital.- Chapter 3. Regulating i-voting within countries and parties.- Chapter 4. Studying Digital Parties: Methods, Challenges and Responses.- Chapter 5. I-voting regulation within digital parties: the case of Podemos and Five Stars Movement.- Chapter 6. Cyber-Parties' Membership Between Empowerment and Pseudo-Participation: The cases of Podemos and the Five Star Movement.- Chapter 7. Anti-Party Digital Parties between Direct and Reactive Democracy. The Case of La France Insoumise.- Chapter 8. How to remain indispensable in the 21st century? The digital adaptation of PSOE and PSP in a crisis context.