I met Chris in the Fall of 1975 at the University of Utah. When we first met I thought he was a new graduate student, in part due to his long pony tail and beard. Then to my surprise I discovered that he was a new instructor in the department.  During that time of few jobs the department had started a new instructor program and Chris was  a recent graduate who had accepted a three year instructorship.

His presence was a big shock to all the graduate students at Utah since he appeared to know more mathematics than many of the full professors. It wasn't long before  he became involved in helping many of the graduate students with their research. This is not what one would expect of a visiting instructor.  As we had become friends he asked if I would like for him to be on my graduate committee and that was probably one of the major turning points in my life.  From that time on we have remained in contact with each other and good friends. 

Chris' research flourished while he was an instructor at Utah.  On one particular occasion Chris walked into the coffee room where I was sitting and it was clear that he was elated. He asked me to read a letter that he had just received from Jean Dieudonne. It was  a hand-written personal letter to Chris  accepting  a paper Chris had submitted to his journal and commenting how much he liked the work (which he  personally had read, reviewed and accepted) - this  is an extraordinary event.

In 1977 I graduated and accepted a three year instructorship at Texas Tech University in Lubbock Texas and Chris continued his instructorship at Utah.  As it turns out I maintained a close contact with Utah even after leaving and returned many times to visit friends.

One story during this period that Chris liked to tell was  the following. The University of Utah had made it policy NOT to readily promote their instructors except under extraordinary circumstances. Recognizing Chris' exceptional talents the  department was considering him  for just such a permanent  position. Letters were solicited from leading mathematicians but one letter turned out to be negative - Apparently someone at Harvard said he would not consider hiring Chris. Of course Chris did not find this out until some years later when someone told me and I told Chris.  At this same time, and unbeknownst to Utah, Roger  Brockett was in the process of trying to hire Chris at Harvard. When Utah acted a bit hesitant about Chris (due to the letter) and with Harvard wanting him, in 1978 Chris  left Utah (before the end of his instructorship) and accepted a dual appointment at Harvard -- a tenure track position in the Division of Engineering and Applied Sciences at Harvard and a position in Mathematics.  Chris and Roger did great research together from 1978 to 1984   producing several works  that are still widely quoted today.  During this time he was promoted to associate professor and he had several great students.   

During my first year at Tech the third International Conference on the Mathematical Theory of Networks and Systems was held in Lubbock and Chris came to the conference. Over the next few years  Chris came to   Lubbock several times and developed a strong relationship with some of the researchers in Electrical Engineering (e.g., Dick Saeks). During these visits we made several trips to Carlsbad caverns,   Palo Duro Canyon and spent most of those days talking  about mathematics. Chris always enjoyed talking  about mathematics, even though he must have known that most of what he was saying was well above my head.  During this time Chris went through a divorce which I believe led to him working even harder at his research. It was during this divorce time that I taught Chris how to kick rocks -- something to do as you walk to help take your mind off your problems.  Chris probably learned more during his time at Harvard than any other time in his life.

In 1981-82  I took a leave of absence and visited Arizona State University.  While there I invited Chris to come and give a talk.  At that time Chris had done some work on power systems  and some engineers at ASU had interest in his work. Between math and engineering I was barely able to raise enough money to pay his airfare.  Of course, once they heard him talk  they loved him. About this same time a major shake-up took place at TTU and the best people from Electrical engineering left the school.  One major player, Dick Saeks,  ended up at ASU and there began a year and a half negotiation to try to get Chris to leave Harvard and take a higher paying job at ASU. 

In the summer of 1984 I held a  Research Associate, RADC, Hanscom Air Force Base just outside Cambridge Mass. Chris let me stay in his apartment across the street from Harvard. Since it was summer time Chris was in Italy working with Alberto most of the time. But we had a couple of weeks together   and it was during this period that he taught me a lot about Boston and Harvard.  One of my favorite Chris stories during this time was  Chris' ordeal with parking tickets. He was separated from his first wife and  still had the old wreck of a car he had when he lived in Utah. In his neighborhood in Cambridge Massachusetts you needed a sticker (which need to be renewed periodically) on your car in order to legally park on the street -- except for parking meters. For one reason or another Chris had managed to let this his permit expire. This meant he could not park on the street or he would be ticketed and eventually they would apply a boot. For some time he parked at meters and just went out and put money in every few hours but as you might guess he eventually got ticketed. The problem was a big catch 22. He could not renew the parking sticker while he had unpaid warrants but on the other hand he had to park somewhere while the payments of fines cleared. All this took time.  He had already received several parking tickets and was on the verge of being booted if they found his car again.   He first tried hiding his car on the Harvard campus but eventually they started to ticket him also. His final solution to this problem was to park his car in long term parking at Logan Airport for about a week and a half  while all the paid tickets cleared and he was able to get a new sticker. 

Seduced with promises of a huge salary, a center and many positions (including hiring me) Chris accepted the offer and moved to (a home in Chandler) Arizona. The seduction began with Dick Saeks who was now Chair of EE. Chris was given a position in both the math and electrical engineering departments.  Unfortunately, as it sometimes goes with these things,  many of the promises only lasted as long as the dean (or vice president) that made them, and at ASU there was what seemed an annual turnover of administrators.

I could tell that  Chris was somewhat disappointed with ASU's constantly changing their mind but undaunted he accomplished many things scientifically there - especially in his work with Alberto Isidori. He was also able to make a few hires and had many visitors including Giorgio Picci, Alberto Isidori and me. I had a leave of absence visit in 1988 for one semester. Remarried when he went to Arizona, Chris had two daughters which were the love of his life. While writing a proposal in 1988, I can remember Chris holding his daughter Kathleen (her screaming), making and feeding her breakfast and, at the same time, dictating to me  an Air Force proposal.  In my opinion the greatest accomplishment was moving many tons of gravel from the front yard to the back of his house to landscape his yard. We also setup a drip sprinkler system and his yard became a paradise in the desert. There was a hot tub and pool and the two story house had a balcony from which we could watch the beautiful sunsets.  Unfortunately we did not get the chance to enjoy very many evenings relaxing since it seemed we were always busy working when I came to town.  At ASU Chris also ran into problems with parking. It seemed that parking fines and fees was one of ASU's serious fund raising mechanisms. Chris had a little pick-up truck that got a flat tire and no spare so he had to leave his truck in the parking lot. Of course it got ticketed and eventually booted. As he was busy a heck (as usual) it took some time get it all straightened out.  I happened to be there when he went in and paid all the tickets and fines (somewhere over $200). With a new annual sticker we headed to his house where he promptly scraped off the old sticker and applied the new one.  The next day we went in to work at ASU with a clear mind that we could park with worry of police action.  Late that afternoon when we went to his pick-up there was a citation.  We went immediately to try to resolve this issue (thinking it was a carry-over from the old problems). You could have never guessed -- when Chris scraped off the old sticker he had accidentally left a small piece of that sticker on the windshield.  As it turns out this is strictly forbidden and, as I recall, a $50 fine.

So from 1984-1989, he was research professor of engineering and mathematics at Arizona State University.  In 1989, Chris left ASU and assumed the positions of chairman and professor in the Department of Systems Science and Mathematics at Washington University. Chris was happy as chair of SSM but when the dean of the School of Engineering and Applied Science stepped down he had to make a decision. While he did not particularly want to be dean he knew that it was important to have someone he could trust  fill the vacated deanship. So  in 1991  he became dean of the School of Engineering and Applied Science. 

Between 1988 and his death in 2010 Chris and I  worked together on research. Chris, through the Air Force,  supported my     research   during that time and was also instrumental in my receiving two research grants from the NSF. He also provided a huge amount of money for my travel to conferences in the US and around the world. Much of these travel funds came from discretionary money he had as part of his endowed professorship -- The  Skinner Professor of SSM.  Twice we went to Italy together and on one of these trips he paid for us to both fly business class. Probably the only time in my life I will ever do so. Twice we went to Sweden and then there were other trips to The Netherlands, Germany, Austria and Canada.  One Air Force trip required us to be in Washington DC by very early evening and he had meetings until late afternoon in St. Louis. So Chris solved this problem by renting a private jet - Wow! What an experience.

Chris really was an outstanding dean and much loved by the alumni. He raised almost $200 million in gifts for the School of Engineering and Applied Science.  Some specific examples include the following:  At his tenth year anniversary as dean, alumni gave more than $250K for a scholarship fund in his honor. At his fifteenth anniversary, they made an additional gift of more than $350K. Also during his tenure, an anonymous donor named an endowed chair, of more than $1M, in his honor. While dean, the number of endowed chairs rose from eight to 37 and the number of endowed scholarships rose from 72 to 199. These efforts involved a significant amount of travel to visit alumni -- where he found time to do research is hard to imagine -- but he did. 

His research was continuously funded by AFOSR  from the time he was at Harvard -- I believe the first person at Air Force to provide Chris funding was John Burns who was a program director back then. In all Chris brought in over $5 million in support of his research. His research, especially  with Alberto Isidori and Anders Lindquist, was  honored by several awards: the George Axelby Award for the Best Paper in the IEEE Transactions on Automatic Control for the period 1989-1991;  In 1993, he and Alberto Isidori received the prize from the IFAC for the Best Paper appearing in the journal Automatica during the period 1991-1993; Then, along with  Anders Lindquist and Tryphon Georgiou, he again    received the George Axelby Award  in 2003,  for the period  2001-2002.  In all Chris published more than 250 papers.

Besides his many accomplishments as Dean he  had  at least 19  PhD students. Some  of his students have become quit famous in their own right and all have had successful careers. The ones I know personally and who are outstanding mathematicians are:

David Delchamps (1982);

Bijoy Ghosh (1983);  

Tony Block (1985);

Bengt Martensson, (1986);

Xiaoming Hu (1989); 

Stefano Pinzoni, (1989)

(Alex) Xiaochang Wang (1989);

Joachim Rosenthal, (1990); 

Xin Zhu, (1991);

Wei Lin, (1993);

John Roltgen, (1995); 

Rowena Eberhardt, (1996); 

Vaidyanathan  Sundarapandian, (1996); 

James Ramsey, (2000); 

Fabio Celani, (2003).

His contributions in time and effort to the scientific community and to his friends and family have been enormous.  

Throughout my career Chris has played a very important role. One thing that comes to my mind and that I will always cherish was Chris introducing me to his advisor, Marshall Stone. Stone autographed my copy of his AMS book on Linear Operators in Hilbert Space -- I will not part with this book. Furthermore Chris' love for mathematics has been as a constant source of inspiration in my career and he has   played a significant role in my life for well over 35 years both professionally and as one of my best friends. As a final example, nearly all of my letters of support for tenure and promotion to Associate Professor and Full Professor at TTU came either directly from Chris or from others that I met through Chris. I believe that without his help I might well be back in Idaho building fence instead of a senior professor at a research university. I could go on for pages with examples I think it is time to stop.  We miss you old friend.