Twenty years ago, in September 2006, I sat down to write my first column for this paper. I did not know then that I would still be writing it two decades later, or that this particular column would be my last. It seems fitting that my final subject is transition, because I find myself, at this moment, keenly aware that our lives are literally a series of big and small transitions. As Kim Kwang-seok’s famous song, “Thirtysomething,” says, “Every day is a farewell.” This spring I did something I never thought I would do: I left a government job I had held for 19 years. It was stable, familiar, and safe in the way that only two decades of institutional memory can make a job feel. But it had also become a known quantity, and I wanted, before I got too old to want such things, to co-create, with other passionate and committed people, what I believe will improve everyone’s lives in critical ways. So, I took a position in the private sector, less secure, less predictable, but full of the kind of professional possibility I had not let myself imagine in years. That decision did not