Book excerpt: The Digital Single Market (DSM) 2014-19 was the largest component of the European Union's Single Market programme, comprising numerous Directives, Regulations, and instruments aimed at facilitating cross-border digital services. With one-fifth of service exports stemming from the digital sector, the DSM was vital for the UK, with the EU representing its largest export market. Brexit and the Digital Single Market examines the important historical role of the UK in DSM development, the consequences of Brexit for the UK's digital sector, and future EU and UK policy trajectories. Assessing both vertical sectors and horizontal policies, this book demonstrates how the UK acted as a policy entrepreneur in pushing for a deregulatory framework by exploiting temporal events historically. The current challenges presented by Brexit are discussed in detail, closely observing topics such as the loss of the country of origin principle and freedom of movement, changes to copyright and VAT regimes, complications with cross-border data transfer, administrative procedures, and international taxes on digital products and services. Brexit and the Digital Single Market illuminates how the UK continues to innovate in the digital sector but is constrained by external factors both at EU and global levels. It also considers how EU policy is taking a new direction in its 2020 Digital Strategy programme, which leans towards greater protection of European champions and digital sovereignty, a tightening of its data protection regime, and greater regulatory intervention in digital markets. Timely and unprecedented, Brexit and the Digital Single Market is the first volume to comprehensively cover the implications of Brexit for the EU's DSM. This is an essential read for students and academics in political science and law and those from the civil service and government working within the digital sector.