Blockchains and smart contracts are emerging technologies that pose unique challenges for legal systems. This book outlines the extent to which these new and innovative technologies could have potentially disruptive effects on contract law in Europe. It does so through a comparative, three—part analysis of the recognisability and effects of smart contracts in European legal systems. First of all, in light of the technologies’ transboundary nature, the book employs a comparative approach, considering French law, German law, English law, and Dutch law to analyse the impact on the different systems of contract law. While doing so, it also addresses the formation, interpretation, and vitiation of contracts. Secondly, it analyses the impact of these technologies on European laws regarding unfair terms in consumer contracts and argues that the existing rules should be applied to smart legal agreements in business—to—consumer relations. Lastly, it analyses the current European rules of private international law on the basis of which jurisdiction and applicable law are developed. In this respect, the book concludes that the vast majority of these European rules are “smart contract—proof”.