The John Adams Institute for Accelerator Science is a centre of excellence in the UK for advanced and novel accelerator technology. The Institute provides expertise and training in accelerator techniques, participates in research and development, and promotes advanced accelerator applications in science and society at large.The JAI is a joint venture between the Departments of Physics in the University of Oxford, Royal Holloway University of London and Imperial College London.The JAI is physically located in the Denys Wilkinson Building (part of the Physics Department) at Oxford, in the Wilson Building (part of the Physics Department) at Royal Holloway and in the Blackett Laboratory building of Imperial College.The Cockcroft Institute, a similar joint venture between the Universities of Lancaster, Liverpool and Manchester based at the Daresbury Laboratory in Cheshire, was created at the same time.These two institutes, together with the STFC Accelerator Science and Technology Centre (also at Daresbury), form the core of accelerator R&D and training in the UK.