“Open Access” refers to free access to scientific publications over the internet. This concept is the subject of a lively debate among the research community, libraries, publishers and funding bodies. Researchers and libraries typically support open access, calling for better dissemination of research results as a key ingredient for stimulating innovation and research excellence. Many publishers, on the other hand, are sceptical of open access, warning of the potential negative effects it might have on valuable aspects of the current publishing system, such as peer review. Finally, research... funding bodies are investigating open access as a way of improving the return on their investments in research and development. Against the backdrop of this debate, new publishing business models are being developed. Copyright issues, quality assurance and digital preservation are generating further discussion. This handbook intends to inform stakeholders and the society-at-large of the opportunities and challenges surrounding open access, and to promote a broad and inclusive debate on the future of scientific publishing in the European Research Area.