It was during June of 1979 that I first started to get to know Chris. As a third-year Ph.D. student at Harvard, I was working with Peter Caines on new approaches to nonlinear estimation. I was also itching to figure out someplace to use what I’d sort of learned from Raoul Bott’s fabulous course on differential geometry. Chris was the in-house master, I was told, and while floating a few things by him I referred obliquely to one item I’d noticed that I figured everybody knew about already. Apparently everybody didn’t know about it, and Chris managed to work it into his talk at the Workshop he co-hosted later that month. I guess he figured it would be a good icebreaker for me in case I managed to overcome my shyness and try to talk science with some of the hall-of-famers at that meeting. Much to my chagrin, as I later told Chris, lots of the ensuing conversations began something like, “So, what other theorems do you have?” That made him laugh.

So many memories. His energy, quickness, mathematical brilliance, and personal warmth. Countless conversations over beers at the Plough and Stars or the Wursthaus or 33 Dunster Street or that sketchy place on Mass. Ave. between Harvard and Porter Squares whose name I’ve long forgotten. Frequent sumptuous dinners at La Groceria in Central Square, always with him treating me. My Ph.D. defense party at his apartment on Bowdoin Street in Cambridge, at which I enjoyed his first wife’s amazing chile con queso and absconded with the recipe, much to my family’s delight over the ensuing years. Visits to Cambridge after I’d moved to Ithaca, sleeping on the couch at Chris’s place and enjoying morning cappuccino made with his old Pavoni espresso machine, which I inherited when he upgraded to what he called his nuclear-powered Pavoni. I still have that old machine. Who knew that an Ivy Leaguish kid from the halcyon New Jersey suburbs and a bus driver’s son and tough schoolyard basketball player from the Bronx — who, incidentally, guarded future star Dean Meminger while in high school — would hit it off so well? We ate, we drank, we talked, we thought, we wrote together.

But most of all we laughed. People who laugh often and at similar things tend to get along well. At first I was amazed by what appeared to me to be an unusual match between Chris’s and my senses of humor. The match wasn’t perfect — I’ll admit, for example, I’ve never been a big fan of the LVP — but our agreement on what was funny seemed uncanny. Over the years, though, I came to realize that Chris knew how to push everybody’s funny buttons. If you had a sense of humor, Chris could read it and charm you with his mastery of it.

Yes, Chris told some great jokes, but it mostly wasn’t about the jokes. Sometimes they were meta-jokes. Chris loved the way Anders Lindquist told one particular slightly off-color one-liner about Mickey and Minnie Mouse. The joke itself wasn’t especially great, but Chris so loved Anders’s delivery that he demanded Anders tell the joke again whenever a new audience mem- ber turned up. Chris picked up on my personal fascination with people’s quirks of speech and writing and with funny word-stuff in general. To get to Chris’s place in Cambridge, you turned first on Linnaean Street. Why not Linnaeus Street, he asked? Would you have a Darwinian Street or a Hamiltonian Street? Yeah, we both got a kick out of that one. We also loved how distinguished older mathematicians, mostly European, called Morse Theory “The Morse Theory.” We decided that to give due credit to Bott for his generalization of Morse’s results, we’d call it, between us, “Theory of the Morse and of Bott.” Once in a talk I caught myself just before saying “Theory of the Morse,” at which point the listeners probably wondered why I laughed out loud. Then there was the period during the eighties when Chris got into the habit of using “viz.” a whole lot in his papers. When I called him out on it, he said, “Just call me the viz. kid.” Indeed.

While at Harvard, Chris made regular pilgrimages to Amherst to visit his eminent Ph.D. advisor Marshall Stone. I made myself a silent promise that I would pay Chris similar visits after I graduated. I did for a while, but you know how things can go. Life presents new challenges and changes in direction. Chris’s and my research paths diverged slowly, and I became more heavily involved with the parts of my job focused on undergraduate education and advising. I hadn’t seen Chris in at least ten or fifteen years when I learned of his passing. As I said to a colleague when I relayed the news, I think I’m one of the lucky few with a 100 percent positive recollection of his advisee-advisor relationship in graduate school. Yes, I was close to Chris a long time ago, but it seems like yesterday to me. I’m smiling right now as I think back on those days.