This book delivers a comprehensive examination of the legal systems that regulate the responsibilities of intermediaries for illegal online content in both the EU and the US. It assesses whether existing systems are capable of tackling modern challenges, ultimately advocating for the introduction of a double-sided duty of care, requiring online intermediaries to do more to tackle illegal content whilst also better protecting their users' rights. Key features include: *⊂ discussion of the fundamental rights implications of increased intermediary responsibility *⊂ critical appraisal of the current EU system, as laid down in the e-Commerce Directive, and recommendations for reform *⊂ a detailed examination of US intermediary liability law, namely Section 230 CDA and Section 512(c) DMCA *⊂ an overview of key developments in law and in practice in relation to all types of illegal online content, including copyright-infringing content, child sexual abuse material, terrorist content and hate speech *⊂ analysis of the latest regulatory developments, including the copyright in the DSM Directive, the amended Audiovisual Media Directive and the Terrorist Content Regulation. This incisive book will be a key resource for practitioners and policy makers working on issues relating to intermediary liability and illegal online content. Deploying the relevant case law, legal literature and legislative history of the topic, it will also be of value to students and academics in the field.