Tom McGrath writes: “A public library is, depending on your choice of metaphor, either an act of faith or a bet. The proposition: If we can make information and ideas—in short, human knowledge—easily accessible to average people, then they’re not only likely to lead richer and more productive lives, but they are also more likely to contribute to making the overall community richer and more productive. As gambles go, it’s a pretty smart—and safe—one.”