Introduction: The e-book and its associated technology have emerged as a disruptive technology over the past ten years. The aim of this paper is to discuss some of the consequences of this development, based on the work of the e-books in Sweden research projects. Argument: To explain the impact of the e-book phenomenon we use Winston's theory of technological innovation, with particular reference to the "supervening social necessity," the combination of factors that turns an innovation into a marketable product. As a result of the technology all aspects of the production, distribution and use of books is affected. Sectoral and cultural variation: The e-book is having different effects in different sectors and in different parts of the world: rapid development in the USA, slower in France and Japan; rapid development in academic libraries, slower development in public libraries, from country to country. These differences suggest that one supervening social necessity may be needed to explain the divergencies. Conclusion: There is a great deal of exaggeration of the impact of the e-book, based mainly on its influence in the USA. Development in other countries is taking place more slowly and differently and in "small language" countries like Sweden, the pace of development, except in academic libraries is likely to be slow.