HERA: The accelerator and the physics

In the first part of this report the author discusses the electron-proton colliding beam facility HERA and gives an update of the status and the machine parameters. The physics programme is discussed in the second part. In 1979 a detailed feasibility study of the project was organized by the European Committee on Future Accelerators (ECFA) and this was followed by a technical design report prepared by DESY in collaboration with other institutions. This work is the result of a formal proposal to the German authorities to construct a large electron-proton colliding beam facility designed to collide 820 GeV protons with 30 GeV electrons in four interaction regions. These studies contain the basis for several workshops. Besides Germany, institutions in Canada, France, Netherlands, Israel, Italy and the United Kingdom have expressed interest in joining the HERA project. The collaboration is modeled after the construction of large experimental facilities; the collaborating institutions contribute machine components (built in the home countries) and manpower