For millennia, laws have ordered society, kept people safe and promoted commerce. But until now, laws have only had one subject: humans. Turner argues that the rise of artificial intelligence (AI) presents novel issues for which current legal systems are only partially equipped. These include questions of responsibility, rights and ethics. Defining AI is a difficult exercise but without this prerequisite, creating a theory of regulation is impossible. Turner adopts a functional and legal definition which focusses on AI’s ability to take decisions based on principles. Turner shows that AI is becoming increasingly important, and unless we act now it may become too late to shape its development.