To Rudolf E. Kalman: A Personal Goodbye [Historical Perspectives]

I visited Prof. Rudolf Kalman on Sunday, June 12, 2016, three weeks before he passed away peacefully at his home in Gainesville, Florida, on July 2 (Figure 1). I had just learned of his deteriorating health, and I flew into Gainesville to see him for, as it turned out, one last time. He was undergoing chemotherapy at the time, and the signs were not encouraging. However, he was well cognizant that the end was near; he told me so and suggested that I would be writing his obituary very soon. Naturally, my reaction was to provide encouragement about the state of medicine and the abilities of our health-care professionals, to which he expressed doubts and joked. He brought up the fact that President Nixon declared "war on cancer" many years ago and then laughingly noted that although cancer had neither army nor generals, cancer is still around whereas Nixon is not.