In cases where I can find no computer files I have adopted the habit of creating a database record for the date and title of John’s lectures, so that if the missing materials turn up later I will have a spot ready to keep track of them. "Methods for Working With Complexity", Polytechnic Institute of Mexico, Mexico City, Mexico, week of January 2, 1988. Is the entry in John’s VITA in his category “PRESENTATIONS.” The seminar series was sponsored by Prof. Elohim of the Institute, and we were guests in his house in Mexico City during the week when John taught the classes. He and Elohim left the house every morning riding to the university in Elohim’s antiquated Volkswagen van. Elohim’s daughter and I spent the days together she practicing her English and I my Spanish as she took me to sightsee and eat in the city. I can not find any paper documents left by John regarding this trip, although I do have several snapshot pictures of Elohim’s house and Mexico City. John brought boxes of his own writings, offprints, and printed office reports to donate to Elohim who was hoping to establish a center for study of systems at his own university. See also my database record ID 225 “Elohim's Library: Bibliography” (Elohim was not his real name, but one he used in writings and lectures. He was a very unusual person, to say the least, but that is another story. John had become acquainted with Elohim at the St. Louis systems conference in 1987)