The organizers of this conference have told us that we should write at least 25 pages of manuscript, but that we may produce as many pages more as we wanted. Perhaps they did not envisage the possible consequences, but we have taken their words at face value.This paper has implied a vast amount of work and archeological activities. We are grateful to SIGPLAN for defining a task to which resources had to be allocated by our institutions and which forced us to write down an account of our work from 1961 to 1971. While we are writing this preface, those years are very much alive to us. We realize that we lived through this period in a state of semimadness, a combination of very hard work, frustration, and euphoria.