This book presents a state-of-the-art overview of blockchains, a significant innovation that has already started to redesign business, social and political interactions. The technology is attracting considerable interest among researchers in industry and academia wanting to study and leverage the potential of blockchains to provide a decentralized and distributed public ledger for all the participating parties. Comprehensively discussing the current and future challenges, opportunities, applications, business models and values, the book appeals to diverse stakeholders, scholars, practitioners and business leaders interested in blockchains.