I must first pay tribute to Klaus Wyrtki, a hero of mine who passed away earlier this year. At a time when ideas about El Niño pointed all over the place, he told me that Bjerknes's hypothesis was the way forward. He was right, of course, but Bjerknes stopped short of explaining the oscillatory nature of ENSO, and it took Klaus's tide gauge data to show that ocean dynamics is the answer. His analysis was masterful, but there would have been nothing much to analyze without his incredible effort to deploy those tide gauges in atolls and islands throughout the tropical Pacific. My magnum opus may fairly be described as translating Bjerknes-Wyrtki into a numerical model.