This book presents as formal papers nearly all of the lectures given at the NATO advanced summer institute on Computer Architecture held at St. Raphael, France from September 12th - 24th 1976. It was not possible to include an important paper by G. Amdahl on the 470V6 System, nor papers by Mde. A. Recoque on distributed processing, Messrs. A. Maison and G. Debruyne on LSI technology, and K. Bowden. Computer architecture is a very diverse and expanding subject, consequently it was decided to limit the scope of the School to five main subject areas. These were: specific computer architectures, language orientated machines, associative processing, computer networks and specification and design methods. In addition an overall emphasis was placed on distributed and parallel processing and the need for an integrated hardware-software approach to design. Though some introductory material is included, this book is primarily intended for workers in the field of computer science and engineering who wish to update themselves on current topics in computer architecture. The main work of the School is well reflected in the collected papers, but it is impossible to convey the benefits obtained from the discussion groups and the continuous dialogue that was maintained throughout the School. The Editors would like to acknowledge with thanks the support of the NATO Scientific Affairs Division, who financed the School, and the European Research Office of the U.S. Army and the National Science Foundation for providing travel grants.