The European Union has introduced key legislation to regulate online platforms: the Digital Services Act (DSA); the Digital Markets Act (DMA); and the Data Governance Act (DGA). This handbook examines the content of these new legal acts systematically. Its main focus is on the DSA and DMA, with a chapter dedicated to the platform-related aspects of the DGA. Under the editorial stewardship of recognised experts in the field, leading commentators provide authoritative and rigorous guidance to the new legislative environment for the digital space.