hroughout my careers in software and philanthropy—and in each of my annual letters—a recurring theme has been that innovation is the key to improving the world. When innovators work on urgent problems and deliver solutions to people in need, the results can be magical.

I am an old man in his sixtieth year. I have entered that decade of life which destroys the last illusion and beyond which lies death, swift or lingering, actuarial or real. I am also poor, incontrovertibly, humiliatingly poor, for the first time in my life.