Memories of ADJ

In this guest column, I wish to present some informal and personal recollections of the exciting early days of ADJ. This time was very important to me personally, and I think was also signiicant for the eld of algebraic speciication. Because these recollections are so personal, they are also necessarily biased, and probably inaccurate in some respects; but perhaps this will just make the result more amusing to read. In 1969, I took up a post in the Committee on Information Sciences at the University of Chicago, and began teaching things like the theories of information, automata and formal languages, and algebraic foundations of computer science. I also attended Professor Saunders Mac Lane's lectures and seminars on category theory. In 1970, Mac Lane suggested that I apply for the 1971-72 Research Fellowship in the Mathematical Sciences, which had just been established by the Mathematical Sciences Department at IBM's T.