OASIS aims to provide an authoritative ‘sourcebook’ on Open Access, covering the concept, principles, advantages, approaches and means to achieving it. The site highlights developments and initiatives from around the world, with links to diverse additional resources and case studies. As such, it is a community-building as much as a resource-building exercise. Users are encouraged to share and download the resources provided, and to modify and customize them for local use. Open Access is evolving, and we invite the growing world-wide community to take part in this exciting global movement.