Regulating technologies, innovations and risks is an activity that, as much as scientific research needs proofs and evidence. It is the site of development of a distinct kind of science, regulatory science. This special issue addresses the question of the standards of knowledge governing how we test, assess and monitor technologies and their effects. This topic is relevant and timely in the light of problematics of regulation of innovation, regulatory failure and capture. Given the enormous decisions and stakes regulatory science commends, it becomes crucial to ask where its standards come from and gain credibility, but also what valuations of technology and appreciations of their risks or benefits do they embed, and who controls them? This special issue contains four papers that look at the construction of regulatory science or, in the terminology adopted here, the authorization and standardization of regulatory knowledge, particularly the role of networks of scientific experts therein.