Abstract: All aspects of book publishing are being disrupted by digital technology. The disruption started more than forty years ago, but its effects have been felt with particular intensity in trade publishing in the last few years since the advent of e-readers and the pervasiveness of inexpensive Internet access. Technology has allowed some of the traditional functions of book publishers to be usurped by other individuals and organizations and this is provoking a debate about what it is that publishers contribute distinctively to the value chain. Traditional roles and responsibilities are shifting and this is likely to intensify in the future.