These are not books, lumps of lifeless paper, but minds alive on the shelves. From each of them goes out its own voice, as inaudible as the streams of sound conveyed by electric waves beyond the range of our hearing; and just as the touch of button on our stereo will fill the room with music, so by opening one of these volumes, one can call into range a voice far distant in time and space, and hear it speaking, mind to mind, heart to heart.
The Immortal Profession: The Joys of Teaching and Learning (1976)