I have been using the first edition of this book as a text for a number of years. This was in a Stanford University first-year graduate course that is taken by students from Electrical Engineering or Computer Science who are interested in computer organization. Because computer tech nology has been changing so rapidly, it became necessary to supplement the text with additional readings. My colleagues and I examined many newly-published books for possible use as texts. We found no book with the same excellent choice of topics and thorough coverage as Dr. Gschwind''s first edition. Springer-Verlag''s request that I prepare a second edition of this book came at a time when I had many other projects underway. Before I de cided whether to take on the project of preparing a revision, I asked many of my students for their opinions of Dr. Gschwind''s first edition. Even I was surprised by the enthusiasm that this rather skeptical and critical group of students displayed for the book. It was this enthusiasm that convinced me of the value and importance of preparing the revision.