I first met Chris during the MTNS 1985 and still remember the Complaint Box for the Conference Participants that he and Anders Lindquist installed:  the box had no bottom and was fixed right over a wastepaper basket. Later on Jean-Pierre and I visited Chris in Arizona and he came several times to Paris with his daughters, Kathy and even with his mother-in-law.  We discussed mathematics many times but only really worked together for the first time after the Les Houches meeting in March 1992. Les Houches is a skiing lodge in the French Alps and Chris was not skiing.  Even so he managed to sprain his ankle and had to stay a week longer than originally planned (he was supposed to attend some other meetings in Switzerland immediately after Les Houches). During  this period  Chris got interested in Riccati PDEs and we began some more serious collaboration. He was joking later on that I had discovered  a way to keep  him at a place but he hoped I would  not give this recipe to anybody else in order to spare his ankles.  I also remember at that time Chris was very preoccupied worrying about keeping his promise to his daughter Kathleen to bring her a Cuckoo Clock from Switzerland.  This problem was resolved while  I was driving him to the Geneva airport when on the way we stopped to buy one.  He looked relieved afterwards.  We completed our paper in St. Louis in May of the same year. The working conditions were more difficult there and  Chris set our first appointment at 6:00 AM.  This sounded like one of his usual jokes, but actually it was not  -- this was the only time of his day left for doing research -- he had to attend a deans breakfast at 7:30 and so on the rest of the day. During several days we worked that early.  He would  enumerate from memory the printing errors that had to be corrected and then we would discuss  the things that still needed to be done. He came a few more times to Paris, once with Renee. He spoke about his research interests after the deanship will be over. 

Chris had a real talent to easily make new scientific investigations, a very pleasing personality and the ability to make  life enjoyable and always full of laughs.  It is impossible to forget his explanation why we should respect a perfect idiot -- he said, it is very difficult to be perfect, nobody is perfect. 

I still cannot get used to the idea that he has gone suddenly and so early.