The aim of this supplement is to explore and critique this ‘blockchain ecosystem’, the politics it tries to hide, and the legal and regulatory ramifications it inaugurates. The following essays do not portray blockchain as providing all, if any, of the answers to the world’s problems. Instead, the challenge is in part to understand the tensions faced by law and regulation in defining blockchain within the ongoing networking, digitalisation, and datafication of the social. Success in this regard will be measured in the coming months and years by the grip that regulatory authorities and governments are able to maintain on the various strands of blockchain research, development, application, implementation, and conduct—a grip, moreover, that is able to be maintained alongside the regulatory conundrums that continue to plague the wider field of network technologies which are themselves still evolving, mutating, impacting, but not necessarily benefiting community or public interest ahead of private, commercial power. Understanding the extent to which law and regulation will play a role in securing democratic accountability of these powerful and far-reaching technologies is or ought to be a key concern for blockchain scholars and practitioners of all stripes.